Patek Philippe 5496R Retrograde Perpetual Calendar in 18K Rose Gold Box And Paper SetThe Patek Philippe 5496R Grand Complication Perpetual Calendar with Retrograde Date may seem straightforward at first glance. However, beneath its clean and easily readable dial lies a remarkable level of complexity! I Introduced a decade ago (2015), this model was somewhat of an oddball at the time in Patek's calendar lineup, with the other models being the more traditional references like the 5139 5140, the cushion shaped 5940, and the 5159 5160