House of Blois chose a wife from the House of Champagne (Adela of Champagne) as a counterpoise to Angevin power. The senior line of the House of Blois became extinct with the death of Joan I of Navarre, wife of Philip IV of France, in 1305. Champagne and Navarre passed to the Capetian dynasty. King Stephen I of England, 1135–1154, was both a member of the House of Blois and the last Anglo-Norman King, being the grandson of William the Conqueror through his daughter Adela of Normandy. A branch of the family was established in Sancerre by Stephen I of Sancerre, a younger
Hugh I, Count of Blois Avesnes and Margaret of Blois. They had 5 children: Through his marriage Hugh became the first count of Blois from the house of Châtillon. It marked the end of the first dynasty of Blois that lasted over 400 years. After the death of Marie, Hugh married Mahaut, sister of Baldwin III, Count of Guînes. In 1226 the Cisterian nunnery Pont-aux-Dames in Couilly was founded by Hugh. Later Hugh, with the assistance of Philip Mécringes, founded a Cistercian nunnery at Troissy called "L'Amour-Dieu" in 1232. Hugh intended to follow the pious king Louis IX when he started on the Seventh Crusade,