Number two on our #SothebysArchives list of the five most complicated pocket watches to sell at Sotheby’s is … the Dent Ultra-Complication, no. 32573, circa 1904. With a total of 19 complications, the Dent Ultra-Complication was the result of a collaboration between the English firm Dent and the Swiss makers of Capt & Cie. in Solliat and Léon Aubert of Le Brassus. Most likely a commission from Elliot Cabot Lee, an American collector and patron of the major English firms, the base movement was ordered through Capt & Cie – Dent’s go-to supplier for its most complicated pieces. The astronomical and perpetual calendar mechanisms were produced by Léon Aubert and are most notable due to the extremely uncommon time of moonrise and time of moonset functions. A double-dialed pocket watch, the front dial is more typical in an austere enamel with stark black Roman numerals displaying the main timekeeping and the perpetual calendar functions. The rear astronomical dial, however, is more unique a...