William of Newburgh or Newbury (Latin: Guilelmus Neubrigensis,Wilhelmus Neubrigensis, or Willelmus de Novoburgo. 1136?–1198?), also known as William Parvus, was a 12th-century English historian and Augustinian canon of Anglo-Saxon descent from Bridlington, Yorkshire.
His major work was Historia rerum Anglicarum or Historia de rebus anglicis ("History of English Affairs"), a history of England from 1066 to 1198, written in Latin. The work is valued by historians for detailing The Anarchy under Stephen of England. It is written in an engaging fashion and still readable to this day, containing many fascinating stories and glimpses into 12th-century life. He is a major source for stories of medieval revenants, those souls who return from the dead, including early vampire stories, and the only source for the bishop-pirate Wimund.
The 19th-century historian Edward Augustus Freeman expressed the now outdated opinion that William was "the father of historical criticism." Indeed, he was very critical of King John, who he describes as "nature's enemy", and in general his discussion of English kings is "loyal but critical and cool".
Newburgh saw his own work as being based on reliable sources, unlike Geoffrey of Monmouth's Historia Regum Britanniae, of which Newburgh was critical, saying "only a person ignorant of ancient history would have any doubt about how shamelessly and impudently he lies in almost everything." He criticised Geoffrey for writing a history that conflicted with the accounts found in the writing of Bede.