Peter I of Alençon
Peter I of Alençon (1251–1283) was a son of Louis IX of France and Margaret of Provence, born at Château Pèlerin during the Seventh Crusade. In 1268 his father gave him Alençon and Perche, and in 1270 he joined the Eighth Crusade to Tunis.
His marriage to Joan of Châtillon in 1272 brought him Blois, Chartres and Guise. After the Sicilian Vespers he aided his uncle Charles I of Anjou, and died at Salerno in 1283 without surviving sons, so Alençon reverted to the crown.