Following the acquisition of Normandy in April 1204, King Philip granted Danmartin the county of Mortain and the honor of Warenne which was centered on the fortresses of Mortemer[1] and Bellencombre.

In 1211, he refused to appear before Philip in a legal matter, a suit with Philippe de Dreux, bishop of Beauvais.

Danmartin brought other continental nobles, including the Count of Flanders, into a coalition with John against Philip.

[3] With the Emperor Otto IV and Ferdinand of Flanders, he took part in the attack on France in 1214 culminating in the Battle of Bouvines.

Commanding the Brabançons, he was on the losing side,[1] but was one of the last to surrender, and refused submission to Philip Augustus.

The historian Jim Bradbury has described Danmartin's last years: Renaud languished in prison, and in pitiful conditions.