The English king William I (ca. 1027-1087), called the Conqueror, subjugated England in 1066 and turned this Saxon-Scandinavian country into one with a French-speaking aristocracy and with social and political arrangements strongly influenced by those of northern France.

William I was the illegitimate son of Robert I the Devil, Duke of Normandy, and Arletta, a tanner's daughter. Before going on pilgrimage in 1034, Robert obtained recognition of William as his successor, but a period of anarchy followed Robert's death in 1035. As he grew up, Duke William gradually established his authority; his victory over a rival at Val-ès-Dunes in 1047 made him master of Normandy. One chronicle relates that in 1051 or 1052 he visited his childless cousin king Edward the Confessor of England, who may have promised him the succession to the English throne.

About 1053 William married a distant relative, Matilda, daughter of Baldwin V, Count of Flanders. She bore him...