This book is the first full length biography of Robert (c.1088 × 90–1147), grandson of William the Conqueror and eldest son of King Henry I of England (1100–35). He could not succeed his father because he was a bastard. Instead, as the earl of Gloucester, Robert helped change the course of English history by keeping alive the prospects for an Angevin succession through his leadership of its supporters in the civil war known as the Anarchy against his father’s successor, King Stephen (1135–54). The earl is one of the great figures of Anglo-Norman History (1066–1154). He was one of only three landed super-magnates of his day, a model post-Conquest great baron, Marcher lord, borough developer, and patron of the rising merchant class. His trans-Channel barony stretched from western Lower Normandy across England to South Wales. He was both product as well as agent of the contemporary cultural revival known as the Renaissance of the Twelfth Century, bilingual, well educated, and a significant literary patron. In this last role, he is especially notable for commissioning the greatest English historian since Bede, William of Malmesbury, to produce a history of their times which justified the Empress Matilda’s claim to the English throne and Earl Robert’s support of it.