Of the four metals of Ref. 5135 produced, the platinum examples were made for the shortest amount of time only from 2006 until 2011.The "Gondolo Calendario" reference 5135 was introduced to the market in 2004, the distinctive and elegant case shape paying tribute to Patek Philippe's watches from the Art Deco period, underlining the continuous popularity of this celebrated epoch. Today, collectors agree that the discontinued case of the 5135 is one of the modern marvels of the art of casemaking. In time, it is believed that the 5135 may become the 5020 of another era in its rarity of production and overall aesthetic appeal. The model is fitted with the automatic calibre 324, incorporating the patented annual calendar function, a proprietary Patek Philippe development introduced in 1996 in the first wristwatch that automatically advances the month, day and date, and only requires a manual correction once a year on March 1.