Monk

In July 1914 Knowles finished at Downside School and immediately moved into the monastery. He was clothed in the September and became a member of the monastic community, being given the religious name of David, by which he was always known thereafter. After completing the novitiate he was sent by the abbot to the Pontifical Athenaeum of St. Anselm in Rome for his theological studies. Returning to Downside, he was ordained a priest in 1922. His research into the early monastic history of England was assisted by the library built up at Downside by Dom Raymund Webster.^[3]

Dom David Knowles became the leader of a faction of the younger monks of the abbey who wanted to resist the growing demands of the school on the pattern of monastic life at the abbey. They advocated a more contemplative life as the goal of their lives as monks. This effort led to a period of major conflict within the community and he was transferred to Ealing Abbey, another teaching establishment, where he resided 1933–1940.^[4]

Academic at Cambridge

In 1944 Knowles was elected into a research fellowship in medieval studies at Peterhouse in the University of Cambridge, where he would remain for the duration of his academic career.^[5]

In 1947 he was appointed as Professor of Medieval History and then, in 1954, he became the Regius Professor of Modern History, a post he held until his retirement in 1963.

He served as president of the Royal Historical Society from 1957 to 1961;^[6] and was the first President of the Ecclesiastical History Society (1961–63).^[7]

While pursuing his academic life at Cambridge, Knowles was eventually, at the instigation of Abbot Christopher Butler, exclaustrated from Downside Abbey and finally released from his vows. Before his death on 21 November 1974 from a heart attack,^[8][9] however, he was readmitted to the order.^[10]

Knowles is best known for his history of early English monasticism, The Monastic Order in England: A History of Its Development from the Times of St. Dunstan to the Fourth Lateran Council, 940–1216 (1940). His three-volume work, The Religious Orders in England (1948–1959), is also highly regarded by scholars in English medieval ecclesiastical history.^[11] In 1962 he published a textbook, The Evolution of Medieval Thought (2nd ed. 1988), that "dominated medieval history courses in U.S. colleges for a quarter of a century".^[12] He has been criticised for excluding nunneries from consideration in Medieval Religious Houses on the grounds that there was insufficient evidence to draw on (a lack remedied in more recent scholarship).^[13]