A former professor of Medieval History at Oxford University, Sir Rees Davies, has died aged 66.

Previously a medieval historian at Aberystwyth, where he helped to alter the understanding of his native Wales, he was appointed CBE in 1995, and knighted earlier this year.

He was regarded as the finest and most influential historian of his generation, who was responsible for the transformation of scholarly study of medieval Britain.

Born in Llandderfel, near Bala, the Welsh language and a keen sense of his own Welsh identity remained with him for the rest of his life.

Among many other appointments he held, he was chairman of the National Curriculum History Committee for Wales, and, until his death on May 16, was chairman of the Ancient Monuments Board for Wales.

He was Professor of History at the University College of Wales, in Aberystwyth, between 1976 and 1995, and its Vice-Principal between 1988 and 1991.

He was appointed the Chichele Professor of Medieval History (Emeritus) at Oxford between 1995 and 2004 and was also a Fellow of All Souls College until his death.

As a teacher he earned respect and affection, and showed a remarkable ability for listening to his students, giving them unstintingly of his time.

He is survived by his wife, Carys, whom he married in 1966, and by a son and daughter.