As you can see on the photos above, the month is visible through a small aperture just above the Roman numeral XII, and the day of the week is just below the Roman numeral VI. From the center of the dial come three hands for the hours, minutes and date. So what is this new type of calendar? Let’s first explain the difference between an annual calendar and a perpetual calendar. Every wristwatch with an annual calendar displays the date, often also the month, and sometimes the day of the week. It indicates all of these correctly every day of the year, except at the end of February. Every annual calendar needs to be adjusted to go from February 28/29 to March 1st.
The perpetual calendar does not have to be adjusted at all. It automatically switches from February 28/29 to March 1st and automatically corrects for leap years. That is, until the next secular year, which will be in 2100.
The new Quadriennium does not have to be adjusted at the end of February, at least in three out of every four years. This means it automatically takes into account that February has 28 days (three out of four years) and jumps to March 1st. Only in the leap year will it need to be adjusted, because the calendar’s mechanism “thinks” that February always has 28 days. Essentially, the Audemars Piguet Millenary Quadriennium is the only watch that needs to be adjusted backwards in February.
Technically, it’s a magnificent timepiece, though some might find the unbalanced dial to be a bit “messy.” The Roman numerals on the left-hand side are larger than those on the right-hand side, the font used for weekdays looks larger than that used for the months, and two “bites” have been taken out of the dial, for the seconds subdial and the balance wheel. The gold screws in the hour/minute dial and the seconds subdial are a reference to timepieces of yesteryear; however, they also distract the attention, as does the red pointer-date hand. Maybe it’s just me, but I prefer the quieter design of older Millenary watches, like the Millenary Piano Forte.
The balance wheel, which is held in place by a large bridge that is beautifully finished by hand, is part of the famous Audemars Piguet escapement. This proprietary AP escapement, with its double balance spring, was originally launched in 2006 inside the Millenary Tradition d’Excellence No. 5, and works without lubrication thanks to its improved geometry. The double hairspring compensates for potential poising flaws, and should improve the watch’s chronometry. Take a moment to watch the video below, which perfectly explains how the AP escapement differs from a regular Swiss anchor escapement.
The Audemars Piguet Millenary Quadrennium comes in a 47 x 42-mm rose gold case. It’s not the smallest watch in terms of diameter, obviously; however, due to the oval case shape it does not wear like a big watch.