Hans Küng, 85, is one of the world's most famous theologians. In 1960, the Swiss native was appointed professor of fundamental theology at the University of Tübingen, Germany. Two years later, Pope John XXIII appointed him to be an expert theological adviser to members of the Second Vatican Council. In 1979, after rejecting the doctrine of papal infallibility, the Vatican stripped him of his license to teach as a Roman Catholic theologian, although he continued to teach ecumenical theology at the university until retiring in 1996. This picture dates from 2004.