The present watch is a very fine example of a complicated timepiece for Louis Audemars' faithful client, the renowned Horloger de la Marine Charles Oudin in Paris and one of his main clients since around 1860.
It features Louis Audemars' early pendant winding and hand setting mechanism, developed by Hector Audemars in 1838 (see Louis-Benjamin Audemars - His Life and Work by Hartmut Zantke, p. 131), and his counterpoised lever, also called "Bishop's crook lever" (p. 192, pl. T92, op. cit).
The case is stamped with Louis Audemars' hallmarks consisting of a capital letter B in a shield for "Brassus", a lozenge-shaped cartouche with the double cross of Lorraine on a heart containing the capital letters "L.A." for Louis Audemars (p. 187, pl. T68, op. cit).
A similar minute repeating perpetual calendar watch with hanging moon phases to 12 o'clock, number 9'864, is described and illustrated on p. 246, op. cit. Amongst Audemars' earliest perpetual calendar watches, the aperture for the moon phases is "hanging" as opposed to the more commonly layout of the moon showing "upwards".
For an 18K gold, enamel and diamond-set minute repeating watch by Louis Audemars and biographical note on the firm see lot 87 in this auction.