[dropcap size=small]A[/dropcap]part from telling time, perpetual calendar mechanical timepieces, as the name suggests, also tell the day, date, month and moon phase without – at least in our lifetime – the need for hands-on correction for the different number of days in February and the extra day gained every four years for leap year; the watch’s mechanism makes all the necessary adjustments to ensure the date is correct.

Perpetual calendar timepieces are more sophisticated than their less complex offshoot – the annual calendar watch, in which you would have to manually push the last day of February – be it 28 or 29 – forward to 1 every year on March 1.

A much sought-after “useful” and enchanting complication watch today, the perpetual calendar timepiece was invented by Englishman Thomas Mudge (1715-1794). A perpetual calendar watch he made in 1762 now resides in the British Museum. It’s the oldest known perpetual calendar timepiece.

Perpetual calendar watches, especially those worn on the wrist, are more linked to Swiss luxury watch company Patek Philippe in modern times. Patek, which also introduced the annual calendar watch in 1996, started making perpetual calendar pocket watches in 1862 and was granted a patent protection for its mechanism in 1889. In 1925, the Geneva-based company made the first perpetual calendar wristwatch using a women’s pendant watch movement it produced in 1898.

Initial production of Patek perpetual calendar watches was small but they played a big role in the days when the company supplied the great industrial barons and financial tycoons of the New World. But with the launch of Ref 1526 in 1941, the first regular series-produced perpetual calendar wristwatches took off – and soon reached out to a wider market.

Patek has continued to launch new perpetual calendar timepieces, the latest being Ref 5320 introduced this year. This latest model, inspired by Ref 1526 which in 1941 kicked off perpetual calendar watches as part of Patek’s regular collection, automatically indicates months with 28, 30 and 31 days and every four years also recognises Feb 29 as a leap day.

A recent exhibition of Patek Philippe perpetual calendar timepieces in Singapore showed the company has created at least 30 models between 1925 and 2017, not counting the multiple complication timepieces which feature a perpetual calendar.