DAUPHIN, is a title which was given to the eldest son of the royal family of France, and presumptive heir of the crown; on account of the province of Dauphiné, which in 1343 was given to Philip de Valois, on this condition, by Humbert dauphin of the Viennois. The dauphin, in his letters patent, styled himself, By the grace of God, eldest son of France, and dauphin of Viennois.