ROBERT II. (c. 1054-1134), called Robert Curthose, was the eldest son of William the Conquerer. Although recognized in boy hood as his father's successor in Normandy, he twice revolted against his father. (See WILLIAM I.) When the Conqueror died in September 1087 Robert became duke of Normandy, but not king of England; although he received offers of help, he took no serious steps to displace his younger brother, King William II. In Normandy his rule was weak and irresolute. He lost the county of Maine, which for some years had been united with Normandy, and he was soon at variance with his brothers, the younger of whom, Henry, he seized and put into prison. In 1089 his duchy was invaded by William II., who soon made peace with Robert, the two agreeing to dispossess their brother Henry of his lands in Normandy. This peace lasted until 1094, when occasions of difference again arose and another struggle began, Robert being aided by King Philip I. of France.
This warfare ended in 1096, when Robert set out on the first crusade, having raised money for this purpose by pledging his duchy to William for io,000 marks. He returned to Normandy in
September I100.
William Rufus died while Robert was on his homeward way, and in Italy the Norman duke was greeted as king of England; but when he reached Normandy he learned that the English throne was already in the possession of Henry I. In July II oi he crossed over to England, intending to contest his brother's title, but Henry met him near Alton, in Hampshire, and an amicable ar rangement was made between them. But there was no lasting peace. In 1106 the English king crossed over to Normandy, and at the battle of Tinchebrai (Sept. 28, 1106), Henry took his brother prisoner and carried him to England. For twenty-eight years Robert was a captive, first in the Tower of London, and later in the castles of Devizes and Cardiff. He died probably at Cardiff on Feb. Io, The chief sources for the life of Robert II. are Ordericus Vitalis, William of Malmesbury and other chroniclers of the time. See E. A. Freeman, History of the Norman Conquest (1870-76), and The Reign of Rufus (1882).