William the Conqueror had men of diverse standing and origins under his command at the Battle of Hastings in 1066. With these and other men he went on in the five succeeding years to conduct the Harrying of the North and complete the Norman conquest of England. The term "Companions of the Conqueror" in the widest sense signifies those who planned, organised and joined with William the Conqueror, Duke of Normandy, in the great adventure which was the Norman Conquest (1066-1071). The term is however more narrowly defined as those nobles who actually fought with Duke William in the Battle of Hastings. This article is concerned with the latter narrow definition. Proof versus legend Over the centuries since the Battle of Hastings, many people in England have claimed that an ancestor fought on the Norman side. While there is sound evidence of extensive settlement in England by people of Norman, Breton and Flemish origin after 1066, the fact remains that the names of only 15 men who were with Duke William at the battle can be found in reliable sources. This group is sometimes called the "proven companions," Many lists and so-called "rolls" of other alleged companions have been drawn up over the ages but, unless new evidence turns up, all are conjecture of no historical value. The three unchallenged sources remain as follows: Reliable contemporary sources The following three sources constitute the only generally accepted reliable contemporary evidence which names participants at the Battle of Hastings. Between all three sources only 15 names result. Gesta Guillelmi II Ducis Normannorum ("The Deeds of William II, Duke of the Normans"), by William of Poitiers, written between 1071 and 1077. The author was born in about 1020 in Les Préaux, near Pont-Audemer, and belonged to an influential Norman family. After serving as a soldier he studied at Poitiers then returned to Normandy to become chaplain to Duke William and archdeacon of Lisieux. He died in 1090. His work is a eulogistic biography of the Duke. The earlier and concluding parts are lost, but the extant part covers the period between 1047 and 1068 and contains details of the Conqueror's life, although untrustworthy with regard to affairs in England. It gives a detailed description of the preparations for the Norman Conquest of England, the Battle of Hastings and its aftermath. The work forms the basis for much of the writing of Orderic Vitalis.