Born in 1928 in Switzerland, Hans Kung was ordained a Roman Catholic priest in 1954, and taught at the Universities of Munster and Tubingen, where he also directed the Institute for Ecumenical Research from 1963. In 1962 he was named by Pope John XXIII a consultant for the Second Vatican Council. He played a central role in the writing of Vatican II, which in 1965 radically modernised key areas of Catholic teaching. He has since the early 1960s questioned such traditional church doctrines as papal infallibility, the divinity of Christ, and the dogma of the Virgin Mary. In 1979 the Vatican banned his teaching as a Catholic theologian, provoking huge international controversy, and in 1980 a settlement was reached that allowed him to teach under secular rather than Catholic auspices. Dr Kung is the only living Weidenfeld and Nicolson author with an entry in the Encyclopaedia Britannica.