Reginald I of Dammartin

Renaud of Dammartin (c. 1165–1227) was the eldest son of Alberic III of Dammartin and a childhood friend of Philip Augustus. In 1191 his father abducted Ida, Countess of Boulogne, and had Renaud marry her, making him count of Boulogne. In 1203 he and Ida granted a charter to the merchants of Boulogne.

In 1212, after Philip seized his lands, Renaud allied with King John at Lambeth and joined the 1214 invasion of France. He commanded the Brabançons at Bouvines, where he was captured, and spent the rest of his life chained at Péronne, dying in 1227. His daughter Matilda II inherited Boulogne.