In 1985, IWC launched the Da Vinci Perpetual Calendar (Ref. 3750), which rapidly established itself as the company’s top seller. IWC’s head designer at the time, Kurt Klaus, had the ingenious idea of creating a mechanical chronograph with a perpetual calendar, moon phase display and four-digit year display. The complex mechanism is extremely easy in practice because the displays for the date, day, month, year, decade, century, millennium and moon phase can all be set simply via the crown. The circle, one of Leonardo da Vinci’s favourite geometrical figures, determined the round shape of the watch case with its four inner subdials and two semicircular push-buttons. With its outstanding technology and comparatively low price, the Da Vinci Perpetual Calendar launched all those years ago exceeded everyone’s expectations. It became a long-standing bestseller and later a much-loved icon of IWC. The Da Vinci Automatic, Da Vinci Automatic 36 and Da Vinci Automatic Moon Phase 36 models all have a classically simple design and bear IWC’s unmistakable signature.