The Oldest Mechanical Clocks in the World
Several medieval iron clocks claim to be the oldest still working. The evidence is fascinating, and none of the claims is fully settled.
Why 'oldest' is hard to prove
Nobody knows exactly where or when the first all-mechanical clock was made. Britannica says its origin is unknown and suggests the first ones may have been used in monasteries to ring a bell calling monks to prayer.
The oldest survivors are iron turret clocks with no maker's name, no date and centuries of repairs. A document may show that a town or church paid for a clock, but proving that a surviving machine is that very clock is another matter.
Most were also rebuilt. Medieval clocks were regulated by a verge escapement and a foliot, a swinging weighted bar, and after the pendulum arrived in the 1650s many were converted. Some have since been converted back, which makes questions of originality even trickier.
See also: how timekeeping developed over the centuries on OnlineClock.app.
Salisbury Cathedral
Salisbury's clock is the most famous claimant. The city's Experience Salisbury guide describes it as hand-wrought iron, with no dial, made only to strike the hours, and dates it to 1386 or possibly earlier. The same guide credits three clockmakers from Delft by name, an attribution the scholarly sources discussed here do not confirm.
Horologist T. R. Robinson recognized its importance in 1928, noticing that it resembled the Wells clock, according to Keith Scobie-Youngs, writing for the Antiquarian Horological Society (AHS) in 2018; the city guide gives 1929 as the year of rediscovery.
When found, it had a recoil escapement and a pendulum beating 1.7 seconds. In 1956 the clockmakers Smith of Derby converted it back to a verge and foliot so it would work as it originally had.
The date has been fiercely argued. In 1993 the AHS staged a mock trial, the Great Salisbury Clock Trial, and a majority found for the defense. A 2018 rerun returned a not guilty verdict by only a small majority. Critics have suggested the clock could be as much as two centuries younger.
The Cumbria Clock Company, Scobie-Youngs's firm, worked on it in 2007. The city guide says its falling weights are wound once a day and that it works much as it did more than 600 years ago, but the Science Museum notes that Salisbury's clock is not regularly run, so visitors should not count on seeing it in motion.
Wells Cathedral
The original mechanism of the Wells Cathedral clock is now in London. The Science Museum says it was installed in the cathedral in 1392, replaced there in 1837, sent to the Patent Museum in 1871 and has been in the Science Museum's collection since 1884.
It still runs. A museum conservator winds its three gear trains by hand each morning, a job that can take up to half an hour, and the museum says it loses only a few seconds a day. It calls the Wells movement the second-oldest working mechanical clock in England, after Salisbury's.
Like Salisbury's clock, it has been altered over the centuries. The AHS article notes that it began with a verge and foliot and was later converted to a recoil escapement, with an escape wheel inscribed "Samuel Tyte Burcott" and dated July 1807.
Its dial and figures remain in Wells Cathedral. The jousting knights once charged every hour; in the 1960s they were switched to electric power and set to joust every 15 minutes. Even the 1392 date is an interpretation: the AHS article cites earlier research concluding that the most important features of the clock were finished by 1394.
Rye: a dark horse
In his AHS article, Scobie-Youngs, whose firm has conserved the Salisbury, Wells and Rye clocks, concludes that all three are by the same maker because of their many close similarities.
He goes further and suggests the clock at St Mary's Church in Rye might be the earliest of the three. That is a surprise, because an earlier historian argued that Rye's clock was supplied in 1561 by a maker named Lewis Billiard, for 30 pounds. If Scobie-Youngs is right, the relative ages of all three clocks are still open.
Chioggia, Italy
Italy has its own contender. The clock in the bell tower of St Andrew's Church in Chioggia, near Venice, was first installed on the town's medieval Palazzo Pretorio and moved to the church in 1822, before the palazzo was demolished.
Writing in the AHS journal in 2016, Marisa Addomine reports a town council record of 26 February 1386 authorizing money for the clock and its upkeep, and a record of 12 April 1386 appointing a keeper, Pietro Boça, at five pounds a month. In 1423 the clock stopped and a Venetian clockmaker called Paolo repaired its great wheel by setting in four new teeth with a dovetail joint. In 1557 its striking changed from the Italian 24-hour system to two cycles of 12.
The movement ran until the 1970s, when an electric timekeeper replaced it. Addomine's research was prompted by its resemblance to the Salisbury clock, though she does not claim a direct link.
The evidence has limits. The town's accounts go back to 1385, but a fifty-year gap stops the trail there. The present escapement is certainly not original, the movement carries no visible signatures or marks, and the link between the 1386 papers and this particular machine rests mainly on the clock never having left Chioggia.
Old does not always mean medieval
Not every early-looking clock is as old as it seems. The Science Museum's Dover Castle turret clock, found at the castle in 1872, still has its original foliot and crown wheel escapement, yet the museum dates it to 1632 to 1640.
The museum thinks it was probably made in London in the workshop of Leonard Tennant, by one of his apprentices. It is a compact machine, about 89 by 58 by 58 centimeters and weighing 93 kilograms, and is on loan from English Heritage. The museum calls it one of the few surviving public clocks still controlled by its original foliot.
That is a useful reminder that a clock can look primitive without being especially ancient. For the medieval contenders, the honest answer is that Salisbury, Wells, Rye and Chioggia all have serious claims, and none has a signed date to settle the matter. Each case rests on a different kind of evidence: Salisbury on tradition and its primitive form, Wells on cathedral history, Rye on the details of its frame and Chioggia on its town paperwork.
See also: the main types of clocks in use today on OnlineClock.app.
Questions people ask
What is the oldest working clock in the world?
Salisbury Cathedral's clock, claimed to date from about 1386, is the best-known contender, but its date has been debated, and clocks at Wells, Rye and Chioggia also have claims.
Why does the Salisbury clock have no face?
It was built only to strike the hours on a bell, not to show the time on a dial.
Where is the Wells Cathedral clock mechanism?
The original medieval movement has been in the Science Museum's collection since 1884 and is still wound by hand. Its dial and jousting knights remain in Wells Cathedral.
What is a verge and foliot?
The earliest kind of mechanical clock control. A toothed crown wheel rocks an upright rod, the verge, back and forth, and a weighted bar called a foliot swings with it to set the clock's rate.
Keep exploring
Sources
- Salisbury, Wells and Rye - the great clocks revisited (Antiquarian Horology, 2018)
- Winding the Wells - Science Museum Blog
- A fourteenth-century Italian turret clock: Chioggia (Antiquarian Horology, 2016)
- Dover Castle turret clock - Science Museum Group
- The world's oldest working clock - Experience Salisbury
- Clock - Britannica