On the back cover of the case is a portrait of the Russian czar Nicholas I (r. 1825–55) in painted enamel, indicating that the watch was probably commissioned as a present to a subject in recognition of loyalty or service. The movement, with separate cocks for the train of wheels, has jeweled end stones, a lever escapement, a temperature-compensated balance wheel, and a keyless stem-winding mechanism. It is a very early example of a stem-winding movement, made by the original partner in the firm that became Patek-Philippe, still in existence in Geneva. The mechanism is the earliest practical one to have been produced in quantity. It was invented by Antoine Norbert de Patek's subsequent partner Jean-Adrien Philippe (1815–1894) and patented in 1845.