In Perpetuity
Patek Philippe is considered one of the world’s premier watchmakers, and its perpetual calendar watches are particularly exceptional. Nicolette Wong explores the luxury brand’s legacy of creating this coveted complication
n the horological world, there are few watch mechanisms as coveted as the perpetual calendar complication. It is not hard to see why—that a mechanical watch, no larger than 40mm or so across, devoid of any electricity or further informational input, is able to accurately measure the passage of time over a period longer than a human life. That, dear readers, is truly amazing. When we speak of perpetual calendar complications, there is one brand that aficionados always bring up: Patek Philippe. It is no surprise, as the Swiss watchmaker’s dedication to developing the complication has helped it build up its cachet, and become the respected and coveted brand it is today. Before we dive into Patek Philippe’s history with perpetual calendars, however, it behoves us to explain the “calendar” part of the complication. As you know, each year comprises 365 days—except that it doesn’t. It actually comprises exactly 365.2422 days. This odd length is the reason we have 366-day leap years every four years or so. But because the length of a year is shorter than the 365.25 days that this schedule suggests, we need to subtract a leap day from the calendar year every so often. Every centurial year (that is, years ending in 00) will be leap years if they can be perfectly divided by 400. For example, the year 1600 was such a leap year. If it cannot be perfectly divided by 400, however, then it will not be a leap year. The year 1700, for instance, was not a leap year because it left a remainder of 100 when divided by 400. If that sounds complex, that is because it is. And it is this complexity that puts a kink in the timekeeping calculations of perpetual calendars. The beauty of the perpetual calendar is that it is almost perpetual. It accounts for nearly all of the discrepancies in time and date (including varying lengths of months, and four-year leap years) but for one, it cannot account for the non-leap centurial years. It must therefore be adjusted for most centurial years, which are usually 100 years apart. Every perpetual calendar watch will have to be adjusted forward by a day to skip the leap day that the watch would think is occurring. So, the next time you will have to adjust your perpetual calendar will be in the year 2100—or more likely, the task will be left to your progeny, because after all, “You never actually own a Patek Philippe.
The beauty of the perpetual calendar is that it is almost perpetual. It accounts for all of the discrepancies in time and date but for one