Robert Curthose, Duke of Normandy (1087 – 1034)

The eldest son of William the Conqueror, invested as a child with the County of Maine (1052) and made heir apparent to the Duchy of Normandy (1066), but rebelled against his father in 1077. As Duke of Normandy in 1087 his reign was marked by his inability to impose his authority on his barons, the loss of important domains to his two brothers, William Rufus, King of England (Eu and Aumale), Henry Beauclerc (Cotentin, and subsequently Domfrontais), and the demise of Norman influence in the Vexin region and Maine. Robert took part in the first crusade leaving his kingdom as a security to William Rufus. On his return in 1100, Henry Beauclerc had seized the throne of England on the death of William Rufus. Tensions re-emerged and Henry finally defeated his brother at Tinchebray (1106) and kept him prisoner until his death.