He participated in the Third Crusade, at the Siege of Acre and the Battle of Arsuf. He took part in the war in Normandy against the Angevin Kings between 1193 and 1204. Count Robert had seized the castle of Nonancourt from Richard I of England while he was imprisoned in Germany in late-1193.
In 1214 he fought alongside King Philip Augustus at the Battle of Bouvines.
Count Robert"s tomb bore the following inscription, in Medieval Latin hexameters with internal rhyme: Stirpe satus rēgum, pius et custōdia lēgum, Brannę Rōbertus comes hīc requiescit opertus, Et jacet Agnētis situs ad vestīgia mātris. Of which the translation is: "Born from the race of kings, and a devoted guardian of the laws, Robert, Count of Braine, here rests covered, and lies buried by the remains of his mother Agnes." lieutenant is also dated Anno Gracię M. Central Committee. XVIII. die innocentum, that is, "In the Year of Grace 1218, on the Feast of the Holy Innocents.".