Throughout the 1970s and 1980s, Audemars Piguet pursued two seemingly contrasting ambitions: the development of increasingly sophisticated mechanical complications and an adventurous approach to contemporary watch design. The Royal Oak, introduced in 1972, demonstrated the manufacture's willingness to challenge established conventions, while its ultra-thin perpetual calendars helped sustain the tradition of complicated mechanical watchmaking during the quartz crisis. Introduced in 1978, the automatic perpetual calendar calibre 2120/2800 was a remarkable technical achievement, combining a sophisticated calendar mechanism with an exceptionally slender movement. Watches powered by this calibre became an important part of Audemars Piguet's identity, and the manufacture explored a fascinating variety of case shapes, precious-metal combinations and elaborate bracelets to house them.

Dating to the early 1980s, this ref. 5557CA represents a particularly distinctive expression of this creative period. Its approximately 36mm octagonal case combines white gold with a stepped yellow gold bezel, creating an elegant contrast between the two precious metals. The satin-finished grey dial features applied yellow gold hour markers and champagne-toned subsidiary registers displaying the day, date and month, together with a moonphase indication at six o'clock. Beneath the dial sits the automatic calibre 2120/2800, whose ultra-thin construction allows the watch to retain an exceptionally refined profile despite the complexity of its perpetual calendar. Perhaps most striking is the integrated bracelet, an elaborate two-tone basketweave design incorporating yellow and white gold with textured, bark-finished details along the sides of the links.

Watch is in overall excellent condition. The 18K white gold case shows surface scratches and light marks, while the case back retains well-defined engravings. The 18K yellow gold stepped bezel shows some small nicks but remains well defined. The winding crown and calendar correctors are in excellent condition. The dial is in excellent condition, with only some very light marks to the calendar sub-dials. The hands remain clean. The integrated two-tone 18K yellow and white gold bracelet shows surface scuffs, while the bark finish to the sides of the links remains well defined. The AP emblem on the clasp is also well defined. The bracelet is fitted with 18 links and measures approximately 8 1/16” in total length.

Please note: The watch ticks at time of cataloging, but timekeeping is poor and a service is recommended.