On Medieval Clocks

There is a simple, everyday device which influences much of our lives and our time. We take it for granted, and perhaps don’t even pause to consider or realise how much many of the events of out day may be based around it. It sits on many a wall, innocuous, perhaps even largely unnoticed, except when we need to look at it. It is of course a clock, that little contraption which many of us may simply take for granted, but where did they come from, and how did they come to be?

The human desire to keep some track of or measure units of time seems to have been what gave rise to the earliest timekeeping devices, originating perhaps in the ancient times. The earliest clocks may have been ‘water clocks’ sometimes referred to by the fancy technical name of the ‘clepsydra’, and may be defined as “is any timepiece in which time is measured by the regulated flow of liquid into (inflow type) or out from (outflow type) a vessel where the amount is then measured.”[1] Alongside the sundial, they stand as some of the oldest known timekeeping devices we know of, dating back perhaps as far as ancient Babylonia and Persia c1600 BC.[2] The Egyptians had them, the Greeks had them, the Chinese had them, and the Arabs seemed to have them too, as apparently did Westerners.

For many centuries, even millennia, water clocks were used for some form of time keeping though perhaps not necessarily charting hours, or other units, so much as for astronomical measurements. Some were extremely complex, and apparently very large, contained in purpose-built towers, such as that built by one Su Sung in the 11th century. This ingenious device was rather complex in its workings:

          “The water that supplied power was contained in a reservoir…. Water passed by siphon from the reservoir to a constant-level tank, and thence to the scoops of a waterwheel. An endless chain drive slowly turned a celestial globe… one revolution per day. The same waterwheel turned a series of shafts, gears and wheels working the bells and drums which announced the time”. [3]

An important component of this and other devices, which was essential to the creation of mechanical clocks, was the ‘escapement’ which James Hannam defines as a ‘spinning crossbar that allows the gear wheel to turn by only one notch for each of its rotations. Each time the gear moves on by one notch, there is one tick of the clock and the weight driven shaft can turn by a very small amount. A series of other gears translate the turning of the gear wheel into the movements of the hands on the clock face”.[4]

Su Sung’s eleventh century clock had one of the little beauties, but there seems to be some ambiguity over when and how they first came to the Western world, but they seem to have been here by the 13th century. However, it is here that another problem arises, which is that the Latin word for a ‘clock’ used at this time ‘orologium’ could refer to any time piece, mechanical or non-mechanical, or water driven. This means that tracing the origin of the development of mechanical clocks in Western Europe rather difficult.[5]

It is suggested that the earliest mechanical clock was invented in England in 1273, this is taken from the earliest reference to one. Though this claim may be contested, they definitely seem to have existed in some form by the beginning of the 14th century.[6]

Roger of Wallingford,

These Medieval clocks were initially intended as astronomical devices, or contraptions designed to wake up monks to ring the bells for the ‘divine office’ of monks, who had to get up in the small hours of the morning for their services. Considering their use by monks, it is perhaps unsurprising that it was The Abbot of St Albans, one Roger of Wallingford who planned and had made a famous (and non-water

… and a replica of his clock.

operated) mechanical clock for the abbey in the early 14th century. The clock was “an automated astronomical model”, but in spite of it not being a timekeeper in the sense that we know clocks to be, Wallingford’s and other such device seems to have been at the pinnacle of Medieval European mechanical innovation at the time.[7]

The first clocks as timepieces seem to have been developed in Italy in the 1340s, and one was installed a palace at Padua, this machine “automatically indicated the intervals of four-and twenty hours by night and day”.[8]

As with any technology, clocks developed, and on into the later 14th and 15th century they seem to have become smaller, more widespread and began entering the home. Henry V is even reputed to have had one that was shaped like a ship. These clocks had faces more often, and incorporated hour hands, thus were beginning to take on a more familiar form. Interestingly, mechanical clocks could still retain precision even when their size was reduced, and the skilled craftsmen who made them apparently began developing the technology so that by the 15th century, springs had begun to replace the system of weights used in clock mechanisms before.

With clocks, work could be measured by the hour more precisely, instead of just by the amount of daylight, or the amount of work done. Indeed, they have been stated to have bought about a change in public understanding of measurements in medieval culture, alongside other move towards standardization. The increased use of clocks for the measurement of time did apparently have some drawbacks, however, as clocks “subordinated” people to time, causing them to ‘work and live by the hour’, a legacy which is, to some extent still with us today. Workers were not always happy with such changes, and clocks were sometimes destroyed during riots, perhaps because they method of controlling or ‘owning’ their time.

The building of such devices also seems to have fitted into an interesting philosophical and theological framework, emerging and developing in this period. It illustrated the idea of the ordered universe and world as a ‘machine’ with its own divine inventor. Furthermore, the regularisation of measurements of time, arguably better allowed people to understand obeys that order.

Personally, I think that the invention and development of such devices also stands a good testament to the mechanical and mathematical knowledge of medieval people.  Showing that is was within their capability and ingenuity to design and build devices with fairly complex automated mechanisms and improve upon them. So much for medieval Europeans being ‘backwards’, no pun intended.


Gies, Joseph & Gies Frances, Cathedral, Forge and Waterwheel: Technology and Invention in the Middle Ages (New York, 1994).

Hannam, James, God’s Philosophers: How the Medieval World Laid the Foundations of Modern Science (London, 2010).

Simon Schaffer, ‘Origins of Mechanical Clocks’, YouTube, Accessed 7th November 2012, http://www.youtube.com/watch?v=7Ch1y9iPsas&feature=relmfu.

‘Water Clock’, Wikipedia.org, Accessed 8th November 2012, http://en.wikipedia.org/wiki/Water_clock

Image URL for Roger of Wallingford’s clock http://www.flickr.com/photos/jusanord/4631575236/

[1] ‘Water Clock’, Wikipedia.org, Accessed 8th November 2012, http://en.wikipedia.org/wiki/Water_clock

[2] Ibid,.

[3] Joseph and Frances Gies, Cathedral, Forge and Waterwheel: Technology and Invention in the Middle Ages (New York, 1994), p90-91.

[4] James Hannam, God’s Philosophers: How the Mediveal World Laid the Foundations of Modern Science (London, 2009), p163-4.

[5] Simon Schaffer, ‘Origins of Mechanical Clocks’, YouTube, Accessed 7th Novemeber 2012, http://www.youtube.com/watch?v=7Ch1y9iPsas&feature=relmfu.

[6] Ibid,.  p63.

[7] Ibid,. p164.

[8] Joseph and Frances Gies, Cathedral Forge and Waterwheel, p214.

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