Cartier
Paris jewellers who under Louis Cartier made some of the first modern wristwatches: the Santos of 1904 and the Tank of 1917.
Louis-François Cartier took over a goldsmith's workshop in Paris, and under his grandsons Louis, Pierre and Jacques Cartier became an international jeweller with branches in London and New York. The firm was early a supplier to several royal houses.
Louis Cartier designed the Santos wristwatch for the aviator Alberto Santos-Dumont and took inspiration from tanks for the Tank. Under Jeanne Toussaint the panther became Cartier's motif, and the Tutti Frutti jewels with carved coloured stones from India are Art Deco at its most colourful.
Serial and reference numbers on the caseback; the secret signature in one Roman numeral on many dials.