Girard-Perregaux
Girard-Perregaux is a Swiss watch brand that traces its history to Jean-François Bautte's work from 1791. The later name connection arose through Constant Girard and Marie Perregaux, who married in 1856. The brand's historical roots should therefore be distinguished from the period when the compound name came into use.
Historical watches
Constant Girard worked on tourbillon watches with three bridges from the 1860s. The company's history later includes pocket and wristwatches with many movements and names. One famous construction feature cannot identify the entire output.
Identification
Examine dial, case, movement, reference and serial number together. Signature typography and placement must fit the period. Replaced dials, crowns, hands and movements occur, so a single mark is not sufficient proof of authenticity.
Source: Girard-Perregaux, Crafting history.