Patek Philippe Annual Calendar Moonphase

Overall Condition: Great condition overall, case shows light wear throughout consistent with age and use. Dial is like-new. Factory strap shows wear.

In 1991, the soon-to-be graduates at the Geneva School of Engineering were presented with their final project prior to receiving their diploma — simplify the perpetual calendar.

Although the task was easier said than done, their work led to the inception of the annual calendar complication, patented by Patek Philippe in collaboration with the bright engineering minds at the GSE. Five years later, Patek debuted the Reference 5035 which marked the world’s first-ever annual calendar movement and finally bridged the gap between a triple date function and the formidable quantième perpétuel.

This example, a Reference 5146G-001, is housed in a beautifully proportioned 39mm 18k white gold case with a sapphire crystal, signed crown, and a smooth polished bezel. It features a charming ivory white dial with applied indices, recessed subsidiary registers indicating day and month, a moonphase aperture and date window at 6 o'clock, and a matching luminous 'feuille' handset.

Powered by Patek Philippe's Calibre 315 S IRM QA LU self-winding movement, it comes fitted to its signed black alligator leather strap with a signed 18k white gold deployant buckle.

There’s no doubt the Nautilus and Aquanaut have gotten their time in the sun, and even vintage Patek Philippe in general continues to demand the attention of any savvy collector. But let us not forget the high-complication heavy-hitters hiding in plain sight in Patek’s modern catalogs!