For a period, he shared a studio with Dylan Thomas and spent the summers from 1934 to 1937 in Sark, Channel Islands, in the colony of artists which included Mervyn Peake and Peter Scott.
He returned to painting after the war, and exhibited in London, but his wartime experiences had affected him profoundly: he found his earlier atheism dissolving, being replaced by a strong Christian belief.
He preached on intellectual themes, such as the theological purpose of Picasso and Iris Murdoch, and brought in large congregations.
He was a member of the advisory council of the Victoria and Albert Museum from 1976 to 1979, and also lectured on Greek and Turkish art on cruises in the Mediterranean.
He wrote several books, including Theodora: Portrait in a Byzantine Landscape (1978), The Crusades (1980), Suleiman the Magnificent (1983), One Man's Advent (1985) and Richard the Lionheart (1989).