placed to write the Gesta Guillelmi, being both trained as a military knight and serving as a chaplain within Duke William's household. There are no surviving manuscripts of the 'Gesta Guillemi'. André Duchesne published an edition in 1619, although even his (now lost) manuscript was missing its beginning and end. Its present form covers the period from 1047 to 1068, and both starts and finishes mid-sentence. There is also some retrospective material concerning affairs in England after Cnut's death (1035). Orderic Vitalis says that it originally finished in 1071. The Gesta Guillelmi is most valuable as a source for the Battle of Hastings, probably based on first hand oral evidence. The 'History' also serves as a panegyric to William the Conqueror. R. Allen Brown writes: "Within the panegyric there is a wealth of facts and details... most derived from personal knowledge and personal contacts, compiled and intelligently put together by a man uniquely qualified as both clerk and knight, closely connected with the court ... One may add that William of Poitiers must have known his hero from their joint youth up, and stress that as both former knight and former chaplain of the duke he is able to bring us closer to the heart of Normandy in the mid-eleventh century than any other writer of that age or later." Critiques of the Gesta Guillelmi William of Poitiers undoubtedly thought of himself as an historian. He mentions in the Gesta Guillelmi that the duty of a historian is to remain within the 'bounds of the truth.'; but he failed to obey this rule. Antonia Gransden in 'Historical writing in England c. 550 to c. 1307' shows that William of Poitiers was just as much a panegyrist as a historian. She summarises Gesta Guillelmi as 'biased, unreliable account of events, and unrealistic portraits of the two principle protagonists.' Moreover, Orderic Vitalis, who uses the Gesta Guillelmi as his principal source in creating his 'Ecclesiastical History', chooses to omit or contradict many of Poitiers' passages in the Guesta Guillelmi, including denial of King William's mercy to the conquered English; having been brought up in England from 1075–1085, Orderic knew better. However, the Gesta Guillelmi cannot be dismissed; most of the panegyrical passages are easy to isolate, and there is a lot of material that William of Poitiers probably reports accurately. Importance William of Poitier is largely known as a key figure in