William was the illegitimate son of Robert, Duke of Normandy, and Herleva, the daughter of a tanner. His father left on a pilgrimage to the Holy Land in 1034 and died the next year while away, leaving William the title. His mother immediately married and seems not to have had any further part in his life.

Although he was protected by some of his servants, the years until he reached adulthood were a time of civil unrest and the boy had to live part of the time in hiding in Normandy, disguised as a peasant. In 1066 he invaded and conquered England, changing the course of European civilization and world history.

References

Microsoft Encarta 98 Encyclopedia, 1993-97
Green, Robert . William the Conqueror. (New York: Franklin Watts, 1998) (A First Book)
Knox. Ellis L. "William the Conqueror." Available at: http://history.idbsu.edu/westciv/willconq/