Louis I of Blois-Châtillon
Louis of Châtillon, numbered Louis I of Blois-Châtillon, was the eldest son of Count Guy I of Blois and Margaret of Valois, Philip VI's sister. In 1340 he married Jeanne of Avesnes, Countess of Soissons, and from 1342 he ruled Blois and Dunois, holding Soissons through his wife.
In the Breton succession war from 1341, he backed his brother Charles of Blois and helped take Rennes in 1342. He was killed at Crécy on 26 August 1346.