Background
He was a member of the House of Châtillon and was the son of Count John of Saint-Pol (d 1344) and his wife Johanna of Fiennes.
He was a member of the House of Châtillon and was the son of Count John of Saint-Pol (d 1344) and his wife Johanna of Fiennes.
In the Hundred Years' War, he served as a royal commander (lieutenant du roi) in the French army. He fought several battles against the English in Picardy. He was one of the hostages sent to England under the terms of the Treaty of Brétigny of 1360.
He died of the plague shortly after arriving in London. Guy was married to Johanna (d 1392), a daughter of Lord John I of Ligny.