Who married Eustace IV, Count of Boulogne?

Eustace IV (c. 1129/1131  – 17 August 1153) ruled the County of Boulogne from 1146 until his death. He was the eldest son of King Stephen of England and Countess Matilda I of Boulogne. When his father seized the English throne on Henry I's death in 1135, he became heir apparent to the English throne but predeceased his father.

Constance of France (c. 1126 – c. 1190) was a French princess of the House of Capet, the only daughter of Louis VI of France and his wife Adélaide de Maurienne. Amongst her siblings was Louis VII, who succeeded their father in 1137.