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A Measure of Sacrifice

Nick Szabo


By the late 13th century western Europeans had developed a new culture. They possessed a unique combination of the craft skills to make clocks, and more importantly, growing use of relationships that benefited from more precise coordination in time. Almost simultaneously, again uniquely, in the late 13th or early 14th century these Europeans started making and using two very different kinds of clocks – the mechanical clock and the sandglass. The technology of the mechanical clock was independent of that of the sandglass, but they played complementary roles in their function. As a result they appeared and were widely used at the same time and place in history.

From an engineering perspective the mechanical clock with its novelty, the escapement, was by far the more important invention. In terms of its impact on contemporary temporal relationships, the mechanical clock and sandglass were of similar importance. The main innovations were the restructurings of the relationships themselves. Chief among these was the time-rate wage, which played a leading role the economic revolution that started in the late Middle Ages. Between the 14th century (by which time the sandglass and mechanical clock had been invented and the use of the time-rate wage was accelerating) and the 19th century (when slavery and serfdom finally disappeared in the First World) occurred the most rapid transformation of economic institutions in human history. During this era physically coerced labor gave way to worker choice; serfdom and slavery succumbed to the time-rate wage. First with the bell towers, then with their new clocks, Europeans measured with increasing accuracy and integrity the quantity of a most basic human quality – the sacrifices we make for each other.

Long before the 13th century, the time of day was important to Europeans. Rome was filled with sundials, and medieval Europe’s bell towers were the tallest structures in their towns. That most common unit of value in custom and contract, the main measure of sacrifice, the day, was carved into smaller chunks. Bell towers aurally subdivided the day that the sky visually delimited. The mechanical clock and the sandglass greatly improved this accounting of sacrifice. With better clocks an hour’s worth, or precisely a day’s worth, of labor specified in a work agreement could now be securely verified. Other relationships as well could be coordinated—a meeting, an inspection, an auction, the time for opening a market could be planned with far less time wasted waiting for lagging participants.

Fair broadcast and verification of time was thus of fundamental importance to the most common contractual relationship in the new European cities. In agricultural societies, including medieval Europe, serfdom and slavery had provided most of the labor. Most workers in a modern economy earn wages based on a time rate. Along with or following the rise of the time-rate institution—including the contracts themselves, the laws and regulations governing the contracts, and the technology to fairly measure the principal quantity – came the growth of related economic institutions, such as the joint stock company. These institutions enabled a boom in productivity and the spectacular rise of Europe from its darkest ages to the modern era. We will now chart the rise of the clocks and the institutions they supported.

Ancient Time

Artemidorus wrote in the second century A.D. about how to interpret dreams involving clocks: “A clock signifies occupations and undertakings, movements and the start of transactions. Men keep their eyes on the time in all that they do.”4 Two centuries earlier Plautus, a comic writer of the Roman Republic, had a idler (a “parasite”, a perpetual welfare case) character cry out against responsibility as measured by time:5

“The gods confound the man who first found out
How to distinguish the hours. Confound him too,
Who in this place set up a sundial,
To cut and hack my days so wretchedly
Into small pieces! When I was a boy,
My belly was my sundial – only surer,
Truer, and more exact than any of them.
This dial told me when ‘twas the proper time
To go to dinner, when I ought to eat;
But nowadays, why even when I have,
I can’t fall to unless the sun gives leave.
The town’s so full of these confounded dials!”

Plautus’ idler cried out not against the sun, but rather against the use of the sun, instead of the claims of his own desires, as a shared measure of when shared events should occur. The sundials would also have let the idler’s peers know just how much of their day they sacrificed while he dozed and whined. Cosmic events have a crucial integrity property – they occur independently of the manipulation of humans. The movements of sun, moon, and stars are also reliable. They thus served as a fair standard of time.

There did remain the problem that some of the natural events were sometimes open to interpretation. Clouds could obscure the sky, hastening dusk, delaying dawn, botching sundial readings, and obliterating the stars. Rules for the start of work might include such factors as, “as soon as you can recognize the denomination of a coin at arm’s length”, or “as soon as you can recognize a face at three paces.” A commonly used pre-dawn event was the crow of a rooster—not always reliable. Yet another problem, worse the farther north you get, was that the length of sun hours varied with the time of year.

Despite these problems, the fair cycles of nature – in those days, the movements of the sun, moon, and stars; in our day the quantum vibrations of cesium or the pulse of a pulsar – have always served as the ultimate authoritative standard. Observing, and even more importantly communicating this time, is another matter. We need to synchronize our commitments and activities with measures both reliable from error and secure from strategic tampering. We shall now see how the technologies and institutions for such synchronization developed further with the spread of technologies to both independently measure the time and to broadcast a standard version of the time. These technologies revolutionized human relationships.

Commercial Law and the Italian Republics

The economic tyranny of the late Roman Empire had left a devastated polity, a culture in Western Europe that had lost its knowledge of civilized commercial practice and accustomed to seeing government not as a source of any productive assistance to commerce, but only a destroyer of commerce from which commerce must hide. The highly evolved commercial laws and institutions of the Phoenicians, Carthaginians, Greeks, and early Romans were forgotten, starvation gutted the population, economy degenerated to poverty, and civilization died. While the Eastern Empire, now Byzantium, retained a chokehold on East-West trade and only slowly declined, the Western Empire disappeared into the dark ages with its takeover by the illiterate German tribes.

Up to, in some cases, the 20th century, ruins, in stone and text, of the Roman Empire struck the imagination of power seeking warriors, and they tried to re-impose the empire from the top down – calling themselves “emperor”, “Caesar” (Tsar, Kaiser), etc. This was the main political impulse during Europe’s dark ages. While German kings tried to re-impose the Roman Empire from the top down, civic life slowly and fitfully started to re-emerge and reinvent itself in the High Middle Ages. In many times and places in Christian Europe, legal decentralization remained in far greater degree than it had in the Roman or did in the eastern empires.

Centralization, in the form of Eastern-style “kings” and “Holy Roman Emperors”, accompanied the conversion of German war-leaders to Christianity. In northern Italy, the German Lombard kings imposed a royal tyranny through their network of customs booths that restricted and taxed commerce. By the 12th century, however, a number of commercial republics – Venice, Genoa, and Milan foremost among them – had overthrown the tyranny, replacing the Lombard king with the Lombard League of city republics. The customs booths were torn down and the long road back from the Dark ages began.

Thus grew, by the 13th century in northern Italy, a unique civilization. The first ingredients were the oral, decentralized, rich, and diverse tribal customs of the Germans. The second ingredients were the textual remains of the ancient Greek and Roman commercial practices and their theories of law and local debate, as well as elements added later when these practices were subjugated under imperial rule. The result was a synthesis that married the more applicable of the ancient practices and theories with the emerging decentralized legal systems of the Italian republics, to produce new legal codes. Along with these new codes emerged new commercial institutions that went on to produce the unprecedented abundance and freedoms, culminating, for Italy, a few hundred years later in the Renaissance.

In 1288 Bonvesin della Riva bragged in writing about the achievements of his remarkable new civilization. He described the wealth and strength of Milan, a city with 1,500 notaries, over a hundred lawyers, 40 copy scribes, 8 professors of grammar, more than a thousand shopkeepers, and 900 mills. Over 200 bells rang from 120 church towers. Craftsmen made musical instruments, including mechanically sophisticated organs and bell chimers. More than thirty craft shops alone made “sweet-sounding brass bells” attached to horses that chimed in time with their trot. As important to della Riva as Milan’s wealth was its security against tyrants—it could muster over 200,000 men-at-arms from the city and surrounding county.7

Public Goods, Polycentric Law, and the Church

Much of western Europe during this period enjoyed multiple sources of law. In particular, guilds, merchants, and other individuals drafting contracts could choose among the urban communal law, the canon law of the Church, and their own Lex Mercatoria.[Ref: Benson, Berman] The numbers of contracts drafted, as well as the details and integrity of their contents, were unprecedented in history. Typical contracts of the period waive rights under urban or royal law, which left the default (the merchant’s own courts, the Lex Mercatoria). One could, alternatively, write into a contract a “pledge of faith” so that the contract would be covered by canon law. The Medieval Church, as a result of this, as well as of the result of its own production and trade activities, was far more than a religious institution.

Canon law, like the ringing of bells we will discuss below, was meant to be a local public service, available only to a surrounding community that consisted of tithing Catholics. Another such public service, provided in the early and high Middle Ages primarily by the Church, but later taken over by municipal and still later by royal governments, was the keeping of the standard weights and measures, by which the standard weights and measures used in the markets were audited.7

As such, it was most commonly used in local contracts, such as loans to apermanent resident. If the debtor could not pay back the loan, his creditorswould present the contract to the parish priest and ask for anexcommunication. Such condemnation was a common event, but it was damagingnevertheless. In the town church, and in the larger towns this could be alooming dark cathedral, the congregation gathered and listened to the sermon,with the deadbeat separated out. After the sermon the priest from his pulpitread out the name of the oath-breaker, and denounced him, telling thetownspeople what the excommunication was for. Reaching the end of hiscondemnation, all the candles in the church were snuffed out, reflecting thenew state of the condemned’s soul. The bell was tolled, using the particularsequence and bell used for a funeral.6

The deadbeat now could not attend church. If he died while excommunicate, he would be buried in unconsecrated ground, and would usually believe the doctrine that he was condemned to hell. Wroe has described the penance with which a miscreant in a 14th century French town, after having worked out a revised payback schedule between himself, his creditors, and his Church – and in monetary terms the Church was quite lenient—later won back his soul:

The penitent deadbeat stood in front of the congregation, “in an unbelted shirt, bareheaded and without his shoes, holding one of the same thick candles he carried, sometimes, on watch duty. Hot wax dribbled down the sides of it to set on his hand and arm. After a while, his arm ached. He looked like a man who had been pulled out of bed and out of some moral torpor. Most of the neighbors, sympathetically, tried not to moralize about this penance, but some did. The longer a man remained excommunicate, seeming not to care, the more people querie his adherence to his faith as well as his solvency….Inside the parish, therefore, there was no escaping the publicity of debt.”6

Canonical Bells

In our time, the tallest and most expensive buildings belong to some of our most important economic institutions – multinational corporations. The size and expense of our skyscrapers will provide future archaeologists an important clue that these institutions played a big role in our economy. In the high and late Middle Ages, the tallest structures in Europe were bell towers—larger and more numerous in that region than on any other continent. Chartres in the year 1169 boasted a 437 foot tower, the world’s tallest. These towers, besides the churches they were built upon, were also the most expensive structures in town.

Some historians claim that the size and expense of Europe’s steeples and public clocks, like the size and expense of the churches they were built upon, reflected the predominant role of religion in medieval life, as opposed to business in ours. Given that the churches and cathedrals themselves were expensive, this is a plausible claim. However, we have seen that the Church also played a leading role in the economy, both by its own economic activities and by its role in commercial law. The church bells and their clocks also played a major economic role.

Telling time was not the only, and perhaps not even initially the main, function of church towers and their bells. An important early function of the bell tower was as an alarm, to inform the town of emergencies such as a fire or attacking army. The towers also sometimes made a good vantage point to detect such events. They tolled for events such as baptisms and funerals. Timekeeping became its primary function, first in order to call people to mass, but soon as a general service the Church provided to the surrounding Catholic community that supported it. Long before the mechanical clock, residents within a few miles of a church started working their schedules around the canonical hours – sundial-based unequal hours – tolled on its bells.

Thus in many European cities, long before the invention of the mechanical clock, the local church was trusted to ring the hours. Churches, funded mainly by the nearby parishioners, but often also by the city or directly by a guild of merchants, lavished enormous resources to build, operate, and maintain the towers as well as the bells, and later for the clocks that were installed in those towers. The productive synchronization of human relationships funded the bell towers; the bell towers would provide a ready market for public clocks. Thus did in Europe emerge a “virtuous circle” that would advance both its timekeeping technologies and time-dependent institutions beyond those of the other continents.

The time rung on the bells was mainly read from a sundial. By the 11th century these were often supplemented by water clocks. By the end of the 14th century most were using the new mechanical clock, backed up by another new technology of that century, the more reliable and personally secure sandglass.

In the larger and more important belfries were present at least two bell-ringers. They lived up there full-time.4 This arrangement is an exmaple of the pattern of dual control – each ringer served as a check for the other; neither could spoof the time or other bell signals without the collusion of both.

The heaviest and most expensive elements of the towers were the bells. Bells smiths competed to produce the most distantly hearable ringing. The “Maria Angola” bell, cast in 1659 and installed in a cathedral in Cusco, Peru, could be heard up to 25 miles away.8 In Cordova in the 16th century, a cathedral boasted a one-ton bell that could be heard 8 miles away. At the cathedral at Rouen, in 1321, a carillon was installed that played on an array of bells a hymn audible 5 miles away.4 The typical range of a parish church’s bells was 3-5 miles. These bells would primarily be heard and in the surrounding town; larger bells could also be heard by peasants working in the fields miles away.

The most valuable property of the bell tower time was not its accuracy, but its fairness. Even if it broadcast the wrong time, it broadcast the same wrong time to everybody. An employer, even if he was colluding with the Church to bias the sometimes subjective ringing of the canonical hours, couldn’t tell his favorite employees that it was time to go home, while making other employees work extra, and pretend that it was the same time. (In contrast, on our computer networks such “Byzantine” attacks are possible, without advanced safeguards, when “broadcasting” time or other information).

While nearby churches or monasteries provided the public, standard time, workers and employers both often employed their own timekeeping devices as a check. Peasants could tell the time by observing their own shadow against some standard sized object. In Germany and Flanders, even the smallest peasant villages had “quadrants to indicate the hours without the sun”. Miners, working underground, followed work bells, operated by the employers, and passed their signal on through the tunnels by workers banging on tools. As a check, the miners had their own marked tallow candles.4 Despite the public broadcast of authoritative time, few dispensed with the option to check their own independent sources.

Dohrn-van Rossum4 describes how bells came to be rung, not only for the time, but for widely different purposes and groups of people: prayer, funerals, visiting dignitaries, opening and closing the gates, beginning and ending the market, calling meetings, and so on. Often guild regulations were enforced by a guild or city bell rung, independently of the church, to indicate the start of work, breaks, and end of work. By the late Middle Ages, cities and guilds increasingly had their own set of bells. The Church was mainly interested in its own events. It typically rang only four of the canonical hours in the day. More precise times were rung based on the specific event. As schedules and event types diversified, cities grew increasingly cacophonous as more specific events were broadcast to all. Specific events that could not gain access to this scarce “acoustic space” had to remain unrung and thus unsynchronized. A better solution was needed.

Mechanical Clocks

In the 14th and 15th centuries, the expensive bell towers of Europe’s main cities and towns got a fancy upgrade – the mechanical clock. These machines were the high-tech wonders of their day. While most mills were built from wood, from their first major appearance in the late 13th century mechanical clocks were built from finely crafted iron parts.

A very small number of designs for unique water clocks with sophisticated mechanical parts, including some with regulatory mechanisms similar to an escapement, are known from earlier times in China and the Islamic world. They were marvels that showed off their engineers’ prowess. The East’s clocks were designed and used for no purpose other than mimicking the cosmos in gears. They were nice for esoteric research and entertainment. They were not widely built and thus clocks did not, until developed further by the Europeans, transform human relationships like they did in Europe.

The key engineering breakthrough giving rise to the mechanical clock was the escapement. This breakthrough may have derived from one or more of at least four potential sources: the earlier escapement-like water clocks of China, alarm clocks, musical instruments, or the technological ideals of craftsmen and engineers.

Monks, soldiers, and merchants alike often needed to arise with an alarm more reliable than the rooster’s call. Water clocks were expensive to build and operate. Furthermore, the ringing alarm sounds better when it is regular. A compelling case has been made4 that the escapement developed out of the regular alarm ringing mechanism, and fulfilled the need of a clock that would run overnight unattended and produce an alarm in the morning, more reliably and cheaply than a water clock.

Among the musical instruments of 13th century Europe was a circular turntable of bells, each tuned to a different note. At some point, around or before the invention of the mechanical clock, these became automated in the form of a carillon. As with the alarm clock, early mechanisms to induce regular chiming from the carillon resembled the early escapements of European mechanical clocks.4

Two technological ideals arose from the rapidly growing mill industries of high medieval Europe and the corresponding professional craftsmen who designed, built, and operated them. The first ideal was the automata, the goal of mimicking life. Today this goal is still alive and well, in the form of robotics and artificial intelligence. The second ideal was the perpetuum mobile, the goal of achieving unending motion. One inspiration of this ideal was the movement of water mills, which (if designed well enough) would never ceased as long as the water flowed. Also inspiring were the movements of the moon, sun, and stars – “machines” that ran on their own, cycling, so it seemed, for eternity. The ideal of the perpetuum mobile is not today popular, because it became confused with the ideal of a source requiring no energy, which 19th century thermodynamics showed to be impossible. However, reducing friction, noise, and other obstacles to smooth motion are still important objectives for mechanical engineers.

Early public mechanical clocks were also (or even mainly) works of art that both demonstrated the perpetuum mobile ideal – specific mimicry of the sun, moon, and stars in a mill-like machine, and the automata ideal, in the form of parades of crowing cocks, bowing Magi, and a variety of other life-like creations. The technological breakthrough, the escapement, provided the “heartbeat” of these automata while also allowing the long-lived mimicry of the regular movements of the cosmos.

A negotiation can have many possible outcomes, some of them more likely than others. The most likely of these are called “focal points” (also “Schelling points”, after their discoverer). Focal points are often designed and submitted into negotiations by one side or another, both to bias the negotiations and to reduce their cost. The fixed price at the supermarket (instead of haggling), the prewritten contract the appliance salesman presents you, etc. are examples of hard focal points. They are simply agreed to right away; they serve as the end as well as the beginning of negotiations, because haggling over whether the nearest neighbor focal point is better is too expensive for both parties.

There are many weak enforcement mechanisms which also serve a similar purpose. Contemporary examples include the little arms in parking garages that prevent you from leaving without paying, the sawhorses and tape around construction sites, most fences, etc. Violation is easy to do but also easy to see. Civilization is filled with these implicit contracts, enforced more by custom than by strong security or integrity, and embedded in the world.

More subtle examples include taxi meters, cash register readouts, computer displays, and so on. As with hard focal points, the cost of haggling is reduced by invoking technology as authority. "I'm sorry, but that's what the computer says", argue clerks around the world. "I know I estimated 50 to get to Manhattan, but the meter reads 75", says the taxi driver. The parties may assume the machine works fairly, implicitly or explicitly trusting its maker and/or its operator. The machine is perceived by its users to have some property of relentlessness, or the inability of at least the immediate users to undetectably tamper with it. If the mechanism can in fact be tampered, the parties either come to distrust it and move to some other method of verifying their agreement, or they use their own means or a reputable third party auditor, for example the city taxi inspector, to verify the operation of the machine.

The first public clocks, built with great expense and hype, served as such authoritative automata. They were explicitly linked to, and drew on, the relentlessly fair timekeeping of the sun, moon, and stars. It was not long, however, before the listeners to bells learned that mechanical clocks on the vulgar earth, unlike their cosmic counterparts in heaven, could be fudged, reset, or spoofed by the sinful humans who operated them. In one 15th century bell tower the expensive mechanical clock broke down. Instead of fixing it, the clock was replaced by two ringers using sandglasses.4 We’ll have more to say about the integrity—the security and fairness—of public mechanical clocks, and of timekeeping in general, below.

The mechanical clock, and especially its key breakthrough the escapement, are much more important than the sandglass from our point of view. For contemporaries, however, the sandglass was equally or more important. Until the widespread use of small table-top mechanical clocks, the sandglass was the primary means of fair timekeeping. The sandglass was visible to all in a room, and it could only be dramatically and obviously “reset”, it couldn’t be fudged like a mechanical clock.

The accuracy of early mechanical clocks, plus or minus 10-15 minutes per day, was not substantially better than that of late water clocks, and was less accurate than the contemporary sandglass. That mechanical clocks nevertheless spread widely in the fourteenth century may be attributed to (a) its automatic striking feature, which allowed the clock to be struck every hour at lower cost, providing about three times as much granularity with which to schedule events – or six times, where the half-hours were struck, or twelve times where striking quarter hours, (b) the cost of operating a mechanical clock was lower than a water clock, (c) the need, caused by the advent of sandglass reckoning, to augment the sandglass with a longer-term and widely and fairly broadcast equal-hour standard, and (d) the moral authority derived from mimicking the independent, fair movements in the cosmos.

Before the mechanical clock, bell towers used the old system of canonical hours, with some untoward consequences. Because the striking was manual, it was usually done only four times during daylight and once at night. The none (“ninth hour”) was originally rung at roughly (what we now call) 3 p.m. During the Middle Ages it wandered back and forth, finally migrating back through the day until it reached its current spot, noon, in the twelfth century. This may have occurred because lunch (or the breaking of fast on certain holy days) was scheduled for none, but the monks tended to get hungry before then. It may have occurred in the service of laborers who got off work at none instead of sundown, although there weren’t very many of these lucky workers. Any such incentive would operate like a ratchet – errors forward caused hungry stomachs or aching bones and so were corrected; errors backwards tended to be ignored and accumulate. This migration naturally occurred at very different speeds at different localities. Different regions were not fully synchronized until long after clock hours had replaced the canonical hours.

Even with the advent of the mechanical clock, its most fair and secure property was not that it told time more accurately – its accuracy slipped by several minutes per day, and the monks or prelates had to be trusted to not reset it. The secure fairness of the bell tower’s broadcast was the most valuable component of the system. However, the mechanical clock’s improvement in accuracy from up to an hour, to only a few minutes, still greatly increased the ability to coordinate and reduced disputes over, for example, daily work times.


An advancing technology in 13th century western Europe very different from mechanics was glass-blowing. The origin of the sandglass is quite obscure, but its accuracy relies on a precise ratio between the neck width and the grain diameter. It thus required extensive trial and error for glass-blowers to arrive at hour glasses for sand, ground marble, eggshell, and other sized grains, and techniques for mass producing these precisely sized works of glass, besides a ready of market of users, which Europe turned out to be.

There are no demonstrated cases of sandglasses before the 14th century. Manufacture and use of the sand-glass was widespread in western Europe by the middle of the 14th century.10 In 1339 Ambrosio Lorenzetti painted a fresco in Siena, one of the commercial cities of northern Italy, which shows a sandglass as an allegory for temperance (self-control). Mariners in the Mediterranean were likely using sandglasses to measure time and velocity by 1313. By 1394 French housewives were using recipes to make, along with food, glue, ink, and so on, marble grains for an hour-glass:

"Take the grease which comes from the sawdust of marble when those great tombs of black marble be sawn, then boil it well in wine like a piece of meat and skim it, and then set it out to dry in the sun; and boil, skim and dry nine times; and thus it will be good."

Such a recipe presumably creates grains of a size in a precise ratio to a standard hour-glass neck size, thus producing an accurate time.”10

The sandglass, not the mechanical clock, became between the 13th and 16th centuries the main European timekeeper in activities as diverse as public meetings, sermons, and academic lectures. It was also the main navigational and scientific clock during that period.4,10

A Measure of Sacrifice

The most important institutional breakthrough that accompanied the clock, the time-rate wage, was based on a largely implicit idea that grew with the invention of the clock – the idea of time as a measure of sacrifice.

Mechanical clocks, bell towers, and sandglasses provided the world’s first fair and fungible measure of sacrifice. So many of the things we sacrifice for are not fungible, but we can arrange our affairs around the measurement of the sacrifice rather than its results. Merchants and workers alike used the new precision of clock time to prove, brag, and complain about their sacrifices.

In a letter from a fourteenth-century Italian merchant to his wife, Francesco di Marco Ganti invokes the new hours tell her of the sacrifices he is making: “tonight, in the twenty-third hour, I was called to the college,” and, “I don’t have any time, it is the twenty-first hour and I have had nothing to eat or drink.”4 Like many cell phone callers today, he wants to reassure her that he is spending the evening working, not wenching.

A major application of clocks was to schedule meeting times. Being a city official was an expected sacrifice as well as a source of political power. To measure the sacrifice, as well as to coordinate more tightly meeting times, the modern clocks of the fourteenth century came in handy. Some regulations of civic meetings of this period point up that that measuring the sacrifice was important, regardless of the variable output of the meetings. In Nuremburg, the Commission of Five “had to observe the sworn minimum meeting time of four “or” (hours) per day, regardless of whether or not they had a corresponding workload. They were also obliged to supervise their own compliance by means of a sandglass.4

Time-Rate Wages

As commerce grew, more quantities need their value to be measured, leading to more complications and more opportunities for fraud. Measurement disputes become too frequent when measuring too many quantities.

Measuring value is hard. Measuring something that actually indicates value is harder. Measuring something related to value and immune to spoofing is hardest of all.

Most workers in the modern economy earn money based on a time rate—the hour, the day, the week, or the month. In agricultural societies slavery, serfdom, and piece rates were more common than time-rate wages. Time measures input rather than output. Time is the main way we arrange our affairs around the measurement of the sacrifice rather than its results.

To create anything of value requires some sacrifice. To successfully contract we must measure value. Since we can’t, absent a perfect exchange market, directly measure the economic value of something, we may be able to estimate it indirectly by measuring something else. This something else anchors the performance – it gives the performer an incentive to optimize the measured value. Which measures are the most appropriate anchors of performance? Starting in Europe by the 13th century, that measure was increasingly a measure of the sacrifice needed to create the desired economic value.

This is hardly automatic – labor is not value. A bad artist can spend years doodling, or a worker can dig a hole where nobody wants a hole. Arbitrary amounts of time could be spent on activities that do not have value for anybody except, perhaps, the worker himself. To improve the productivity of the time rate contract required two breakthroughs: the first, creating the conditions under which sacrifice is a better estimate of value than piece rate or other measurement alternatives, and second, the ability to measure, with accuracy and integrity, the sacrifice.

Three of the main alternatives to time-rate wages are eliminating worker choice (i.e., serfdom and slavery), commodity market exchange, and piece rates. When eliminating choice, masters and lords imposed high exit costs, often in the form of severe punishments for escape, shirking, or embezzlement. Serfs were usually required to produce a particular quantity of a good (where the good can be measured, as it often can in agriculture) to be expropriated by the lord or master. Serfs kept for their personal use (not for legal trade) either a percentage or the marginal output, i.e. the output above and beyond what they owed, by custom or coercion, to their lord.

Where quantity was not a good measure of value, close observation and control were kept over the laborer, and the main motivator was harsh punishments for failure. High exit costs also provided the lord with a longer-term relationship, thus over time the serf or slave might develop a strong reputation for trustworthiness with the lord. The undesirability of servitude, from the point of view of the laborer at least, is obvious. Serfs and slaves faced brutal work conditions, floggings, starvation, very short life spans, and the inability to escape no matter how bad conditions got.

Piece rates measure directly some attribute of a good or service that is important to its value – its quantity, weight, volume, or the like—and then fix a price for it. Guild regulations which fixed prices often amounted to creating piece rates. Piece rates seem the ideal alternative for liberating workers, but they suffer for two reasons. First, the outputs of labor depend not only on effort, skills, etc. (things under control of the employee), but things out of control of the employee. The employee wants something like insurance against these vagaries of the work environment. The employer, who has more wealth and knowledge of market conditions, takes on these risks in exchange for profit.

In an unregulated commodity market, buyers can reject or negotiate downwards the price of poor quality goods. Sellers can negotiate upwards or decline to sell. With piece rate contracts, on the other hand, there is a fixed payment for a unit of output. Thus second main drawback to piece rates is that they motivate the worker to put out more quantity at the expense of quality. This can be devastating. The tendency of communist countries to pay piece rates, rather than hourly rates, is one reason that, while the Soviet bloc’s quantity (and thus the most straightforward measurements of economic growth) was able to keep up with the West, quality did not (thus the contrast, for example, between the notoriously ugly and unreliable Trabant of East Germany and the BMWs, Mercedes, Audi and Volkswagens of West Germany).

Thus with the time-rate wage the employee is insured against vagaries of production beyond his control, including selling price fluctuations (in the case of a market exchange), or variation in the price or availability of factors of production (in the case of both market exchange or piece rates). The employer takes on these risks, while at the same time through promotion, raises, demotions, wage cuts or firing retaining incentives for quality employee output.

Besides lacking implicit insurance for the employee, another limit to market purchase of each worker’s output is that it can be made prohibitively costly by relationship-specific investments. These investments occur when workers engage in interdependent production—as the workers learn the equipment or adapt to each other. Relationship-specific investments can also occur between firms, for example building a cannon foundry next to an iron mine. These investments, when combine with the inability to write long-term contracts that account for all eventualities, motivate firms to integrate. Dealing with unspecified eventualities then becomes the right of the single owner. This incentive to integrate is opposed by the diseconomies of scale in a bureaucracy, caused by the distribution of knowledge, which market exchange handles much better.13 An in-depth discussion of economic tradeoffs that produce observed distributions of firm sizes in a market, i.e. the number of workers involved in an employment relationship instead of selling their wares directly or working for smaller firms, has been discussed by Coase11 and Williamson12.

The main alternative to market exchange of output, piece rate, or coerced labor (serfdom or slavery) consists of the employers paying by sacrifice—by some measure of the desirable things the employee foregoes to pursue the employer’s objectives. An hour spent at work is an hour not spent partying, playing with the children, etc. For labor, this “opportunity cost” is most easily denominated in time – a day spent working for the employer is a day not spent doing things the employee would, if not for the pay, desire to do.1,9

Time doesn’t specify costs such as effort and danger. These have to be taken into account by an employee or his union when evaluating a job offer. Worker choice, through the ability to switch jobs at much lower costs than with serfdom, allows this crucial quality control to occur.

It’s usually hard to specify customer preferences, or quality, in a production contract. It’s easy to specify sacrifice, if we can measure it. Time is immediately observed; quality is eventually observed. With employment via a time-wage, the costly giving up of other opportunities, measured in time, can be directly motivated (via daily or hourly wages), while quality is motivated in a delayed, discontinuous manner (by firing if employers and/or peers judge that quality of the work is too often bad). Third parties, say the guy who owned the shop across the street, could observe the workers arriving and leaving, and tell when they did so by the time. Common synchronization greatly reduced the opportunities for fraud involving that most basic contractual promise, the promise of time.

Once pay for time is in place, the basic incentives are in place – the employee is, verifiably, on the job for a specific portion of the day – so he might as well work. He might as well do the work, both quantity and quality, that the employer requires. With incentives more closely aligned by the calendar and the city bells measuring the opportunity costs of employment, to be compensated by the employer, the employer can focus observations on verifying the specific quantity and qualities desired, and the employee (to gain raises and avoid getting fired) focuses on satisfying them. So with the time-wage contract, perfected by northern and western Europeans in the late Middle Ages, we have two levels of the protocol in this relationship: (1) the employee trades away other opportunities to commit his time to the employer – this time is measured and compensated, (2) the employer is motivated, by (positively) opportunities for promotions and wage rate hikes and (negatively) by the threat of firing, to use that time, otherwise worthless to both employer and employee, to achieve the quantity and/or quality goals desired by the employer.1

Time-rate employment provides a major productivity improvement over servitude or (usually) piece rates. Time-rate contracts however require a reliable and secure—a fair and independent—source of time. Laborers were, even before the advent of the clock, commonly paid by the day. But how long is a “day”? It couldn’t be just daylight hours; this makes for a longer workday than employer and employer might otherwise agree to, and in northern latitudes it varies quite substantially within a year. With the rather heterogeneous measures of time, employer could cheat the employee out of hours, or vice versa, unless they had a securely independent standard of time.

A Dispute over Time

Dorhn-van Rossum4 describes a remarkable 14th century French legal dispute between vineyard owners and workers. This case illustrates several points. First, it shows how many of the practices of serfdom, including regulation by custom or royal edict rather than by negotiation between worker and employer, were carried over from serfdom to wage labor. Both the wage and working time of these workers were regulated. Second, it illustrates the kind of dispute that could arise with the unequal canonical hours that were rung ambiguously and less often than the mechanical hours. Reliance on the canonical ringing had been required when workers tried to negotiate a working day different from sunup until sundown. Third, this case shows why the clock ringers needed to be trusted by both workers and employers. Hours rung falsely in a given day led workers to measure the sun for themselves, using a quadrant or their own shadow against a fixed size object. Hours that moved over the years, like the wandering none, had the effect that by keeping to the same customary start and end bells, the actual amount of work changed.

In 1392, the vineyard owners sought and received a royal ordinance for Auxerre and nearby areas. This new law specified the longer sunup to sundown hours that the burghers desired and set a maximum wage. Soon thereafter workers who refused to follow the new regulations were arrested. Royal delegates came to Auxerre to hear the dispute.

Both parties had problems defining the work day. The laborers argued that the custom of ending the work day at none, rather than at sundown, violated the custom of ending work in the afternoon, which was “so old that nobody could remember it every having been otherwise.” The working day ended earlier because the heavy soil made for intense work. Furthermore, none in Auxerre was now being rung later than in previous years, “between the fourth and fifth hour of the afternoon instead of the third.” If the workers were correct, the shifting of none to noon, completed in most other places by 1300, had not yet occurred in Auxerre, and in fact had moved in the other direction. Dohr-van Rossum continues his description:

the workers expressed their objection with the help of the new system of reference, [mechanical] clock time, which had long since become established in Auxerre. The only open question is thus how they knew that in the past None had been rung much earlier.

The burghers countered that they faced poor yields and high costs, denied that the shorter work day was customary, and lamented that the royal ordinance was not being enforced. They added a very serious charge – that the workers had tried to incite a revolt like the 1372 peasant uprisings and tax revolts in Paris. Dohr-van Rossum adds:

The burghers drew a clear picture of purposeful reduction of working time that the workers had pursued. At first they had worked to the end of the ringing of None. Then they had left at the beginning of the ringing. Currently they were ceasing work with the cliquet, the pre-signal to the actual ringing. And when the ringing came late in the judgment of the workers, they decided to end the work freely according to the position of the sun. All told they were now working little more than half a day. The historical argumentation by the burghers has flaws. As shown by the draft of the complaint, they were not at all agreed when the workers did in fact cease working in the afternoon. We hear “two hours”, “two and a half hours”, “three and a half hours”, (sometimes with “approximately” added), and finally “long before sundown”.

We see here a transition state between serfdom and wage labor – wage laborers regulated as if they were serfs. The negotiating flexibility of these day laborers was greatly reduced by regulating the workday and the maximum wage. Why did the royal bureaucrats pretend they knew as much or more about such matters than the owners and workers? Intervention by parties higher in the feudal hierarchy had often been required to regulate and control the life-long relationships between serf and lord, lest on the one hand the output available to the lords be reduced, or on the other hand the lords become so oppressive that peasant rebellion, despite its futility in most cases, arose. The political and legal forms and customs that regulated serfdom were often carried over to wage labor, especially where the economy of the jurisdiction, as with royal France here, was still dominated by serfdom. As the European economy matured, in fits and starts, over the next few centuries such disputes would increasingly be solved by negotiations between the most knowledgeable and interested parties, the owners and workers themselves, and put in the form of time-rate wage contracts.

Abstract Events

In many towns and cities of Medieval Europe, schedules were set by negotiations between guilds. The schedules definitions were crude. Most common was sunup or sundown.

For agriculture, the work day of sunup to sundown worked well. Every major culture working the land worked this long day. The start and end times could be verified with integrity. The day was longest in the summer when the demand for work was greatest. The drawback of this strong focal point is that in most cases it excluded the possibility of many alternatives, especially the ability to negotiate a shorter work day in order to moonlight, work on personal projects, or gain time for leisure or family. It also left open for dispute the length of breaks. So dominant was the sunup to sundown tradition that it was often also applied to urban workers, for whom it is far less in keeping with the work demands of their industries.

Since the canonical hours might be rung only four times per day, a custom schedule required a custom set of bells, along with a fair, audited bell ringer.

Cities turned into a cacophony of bells signifying the starts and ends of various events and work schedules.4 Public mechanical clocks, and especially their feature for automatically striking each hour, twenty-four hours per day, allowed for a separation of duties between time-keeping and the planning or scheduling of specific events. As a “level of indirection”, as a computer scientist would put it, this allowed for an explosion of diversity in the daily schedule while decreasing the conflict of the bells to simply a matter of accuracy in striking the hour.

Some useful integrity properties of old methods were lost. Sunup, sundown, “the time it takes to walk across town”, etc. were independently and inexpensively verifiable events or periods. Clock time depended on the security of the clock-room and the faithfulness of the clock wardens, the guys with the keys to the clock-room. The clock warden was a fiduciary. The clock wardens of 16th century Augsburg, for example, had to swear the following oath: “You will swear a learned oath to God and the saints to faithfully regulate, keep, and maintain the clock of the city day and night, with everything that goes with it, and also to faithfully guard and lock the keys to city hall and the clock, including locking and unlocking, also to be faithful to the city and to warn of harm, all this faithfully and without guile.”

On the other hand, people were already and increasingly relying on bell-ringers to ring specific events. Separation of duties between the timekeeper and scheduler, and the automated striker, combined with a locked clock-room, reduced the opportunity and incentive for bell ringer fraud. Rather than resetting the schedule of a specific event that they were familiar with and responsible for, they would be resetting the time for a wide variety of events, with a resulting variety of consequences, and a variety of incentives for the affected parties to verify the time by independent means. Abstract time allowed different kinds of workers, and even different individuals, more flexibility to set verifiable working hours different from the naturally verifiable times of sunup and sundown.

Equal Hours

Since the common simple sandglass measured only equal hours, not canonical hours, it encouraged the use of equal rather than canonical hours in the new public mechanical clocks. The public clock hours were mostly heard in the ringing, not seen in the dial, and a mechanism for ringing the variable hours is devilishly difficult—this also encourage the adoption of equal hours. It is possible, as was done with some early clocks in Europe, and when the mechanical clock was introduced into Japan, to add simple mechanisms and dial marks that allow a mechanical clock to display variable hours – but making a clock automatically ring the variable hours is hard.

The equal hour system operated at two levels. At the public level, a mechanical clock would ring each equal hour. At the personal or decentralized level, the sandglass would both measure time within an hour and provide a check against the still-common instances of public clock unreliability and fraud.

Clock hours, equal and relatively accurate, began to replace the unequal (twelve hours in daylight regardless of the length of day) and heterogeneous canonical hours in contracts, laws, and other institutions, starting before 1330, and had mostly replaced the canonical hours by 1370. The historian Jean Froissart shifted from canonical hours to the new clock hours around 1380.

The Rise of the Time-Rate Wage and the Decline of Serfdom

Expensive public clocks spread to many European towns and cities in the 14th century. What did the Europeans of the time have to say about their costly new clocks? The city of Caen in 1314 installed a clock with the following inscription: “I give the hours voice/to make the common folk rejoice.” While regimentation has its downsides, getting rid of the stress from disputes over the basic issue of what time it is – Artemesia is angry with Bassanio for being late, Bassanio retorts he was early – seemed to bring a great relief and rejoicing to Europe. A fifteenth century petition for a city clock for Lyons declared, “If such a clock were to be made, more merchants would come to the fairs, the citizens would be very consoled, cheerful and happy and would live a more orderly life, and the town would gain in decoration.” By the 16th century, European cities were so well synchronized that Rabelais could state “a city without bells is like a blind man without a stick.” The clock and the bells it chimed synchronized the relations among men.

The productivity of Europe greatly increased over this period. This productivity can be estimated by measuring how it was consumed, including:

  • Increasing the ecological carrying capacity, and thus the population (except as offset by plagues)
  • A vast increase in the quantity, quality, and variety of goods and services beyond basic foods
  • Shortening of the work day and work week.


Clock time is a fungible measure of sacrifice. Of all measurement instruments, the clock is the most valuable because so many of the things we sacrifice to create are not fungible. The massive clock towers of Europe, with their enormous loud and resonant bells, broadcasting time fairly across the town and even the countryside, rather than the last relics of the medieval, were the first building block of the wealthy modern world. The Europeans evolved their institutions and deployed two very different but complementary timekeeping devices, the sandglass and the mechanical clock, to partition the day into frequently rung and equal hours. Europe progressed in a virtuous circle where bells and clocks improved the productivity of relationships; the resulting wealthy institutions in turn funded more advances in timekeeping.

The rise of the cities and the merchant revolution was given a temporary setback by the Black Plague, the very century that the clock was introduced, but thereafter economic growth renewed with unprecedented vigor. The massive change on the farm, the dominant form of industry, in the 14th and successive centuries from serfdom and slavery to markets and wage labor, was caused not only by the temporary labor shortages of the Black Plague, but more fundamentally and permanently by the time-rate contract and the new ability to accurately and fairly verify its crucial measurement of sacrifice, time. Time rates also became the most common relationship for the mines, mills, factories, and other industries that rapidly grew after the advent of the clock.


  1. A good discussion of time-wage vs. piece-rate vs. other kinds of employment contracts can be found in McMillan, Games, Strategies, and Managers, Oxford University Press 1992.  

  2. A secondary source for clocks and their impacts is Crosby, The Measure of Reality – Quantification and Western Society, 1250-1600, Cambridge University Press 1997.

  3. Discussions of the unreliability and insecurity of broadcasting time and other information on computer networks can be found in Jalote, Fault Tolerance in Distributed Systems, PTR Prentice-Hall 1994.

  4. My main source for clocks and their impact is Dohrn-van Rossum, History of the Hour – Clocks and Modern Temporal Orders, University of Chicago Press, 1996.             

  5. Another secondary source for clocks and their impacts is Landes, Revolution in Time, Belknap Harvard 2000. 

  6. The keeping of weights and measures by the Church, and description of the ceremony and consequences of excommunication for breach of contract in 14th century France from Wroe, A Fool and His Money, Hill and Wang 1995.  

  7. Lopez and Raymond, trans. Medieval Trade in the Mediterranean World – Illustrative Documents  

  8. Vicente Goyzueta, “Cathedral of Qosco City” 

  9. The original sources for much of the time rate contract discussion is Seiler, Eric (1984) “Piece rate vs. Time Rate: The Effect of Incentives on Earnings”, Review of Economics and Statistics 66: 363-76 and Ehrenberg, Ronald G., editor (1990) “Do Compensation Policies Matter?”, Special Issue of Indsturial and Labor Relations Review 43: 3-S-273-S. 

  10. The Hourglass Connection, “A Brief History [of the Hourglass]”,  

  11. Coase, R.H., The Firm, the Market and the Law, University of Chicago Press 1988. 

  12. Williamson, Oliver, The Economic Institutions of Capitalism, Free Press 1985. 

  13. Hayek, F., The Use of Knowledge in Society 

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