The perpetual calendar is one of watchmaking’s greatest innovations — a mechanism that automatically knows the length of every month and leap year, with no adjustment needed until the year 2100. Its origins lie in Britain, where Thomas Mudge — best known for inventing the lever escapement — the backbone of almost every mechanical watch since — built the first perpetual calendar in 1762.

By ‘remembering’ the four-year cycle of 1,461 days, the mechanism adjusts for 30- and 31-day months, and for February’s 28 or 29 days. More than two centuries later, it remains one of watchmaking’s most respected complications.

For Bremont’s design team, the challenge was to build a perpetual calendar that still looked and behaved like a pilot’s watch. Most perpetual calendars are delicate dress pieces — admired, but rarely tested. Bremont’s mission is to craft the finest timepieces for Air, Land and Sea, mixing modern British elegance with durability, and style.

As CEO Davide Cerrato explains:

“The combination of a perpetual calendar and GMT function is extremely rare in watchmaking, but for Bremont it gives us the perfect mix of classical sophistication and adventurousness. It had to be as robust as any Altitude watch, easy to use, and durable. It’s intended as an everyday watch, not a delicate item that lives in the safe.”

The solution was clear: a display built for legibility. Hours, minutes, and running seconds are set out with purpose. At 12 o’clock, a rotating globe tracks home time on a 24-hour ring. At 6, a pointer marks the date and at 3, a propeller hand advances the months and leap years in 172 steps across a four-year cycle.

The watch demanded the best in Swiss engineering and British craft. The complication module was created exclusively for Bremont by Agenhor in Geneva, masters of ingenious mechanics.

A key part of the engineering solution lay in seamlessly integrating the base movement with the complication module. Thanks to Agenhor’s mastery of complex mechanisms, several hundred components were elegantly combined into a single, compact movement—enhancing both the functionality and the wearability of this timepiece.

The Altitude Perpetual GMT combines innovative functionality with true elegance, following the aviation-inspired design codes of the Altitude Collection. Every detail reflects the Altitude DNA — from the subtle propeller hands to the Air Force Blue dial and barrel, recalling the colours of RAF uniform.

The 42mm case and bracelet, crafted from lightweight Grade 2 titanium, showcase the collection’s signature three-piece Trip-Tick case construction. Thanks to its precision engineering, the watch delivers the unwavering performance expected of a complex timepiece built to endure for decades – if not centuries.

Each of the 50 limited edition pieces is hand-assembled at The Wing in Henley-on-Thames, Bremont’s home of British watchmaking — and the only end-to-end watch manufacture on these shores.