The Annual Calendar is a complication invented by Patek Philippe.While it plays second string to the perpetual calendar in the minds of most collectors, the reality is that the construction of the annual calendar mechanism is equally challenging, and in some cases, requires even more components. The Reference 5035 was Patek's first Annual Calendar model launched in 1996, and set the bar for all that followed — including those from competitors.The particular annual calendar we have here, a Reference 5146G, is housed in a beautifully proportioned 39mm white gold case with a sapphire crystal, a signed crown, and a polished bezel. It features a luminous sunburst grey dial with applied indices, recessed subsidiary registers, a moonphase aperture, day + month indicators, a date window at 6:00, 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 brown alligator strap with a signed, white gold deployant clasp.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.