Patek Philippe Annual Calendar Moonphase

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 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 piece, a Reference 5146P-001, is housed in a beautifully proportioned 39mm platinum case with a sapphire crystal, signed crown, and a smooth polished bezel. It features a luminous sunburst grey 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 324 S IRM QA LU automatic winding movement, it comes fitted to a signed black alligator strap with a signed platinum deployant clasp and includes its inner and outer box set, leather folio, books, corrector tool and Certificate of Origin dated 2008. This piece packs pedigree, refinement, function and outstanding craftsmanship that can only be expected on Patek Philippe. Any old wristwatch can tell the time. Few truly define it.