an introduction to a 1996 reissue of Guardini's 1954 The Lord. Pre-papal career: 1951–2005 Academic career: 1951–1977 Ratzinger began as assistant pastor (curate) at the parish St. Martin, Moosach, in Munich in 1951. Ratzinger became a professor at the University of Bonn in 1959, with his inaugural lecture on "The God of Faith and the God of Philosophy". In 1963, he moved to the University of Münster. During this period, he participated in the Second Vatican Council (1962–1965) and served as a peritus (theological consultant) to Cardinal Frings of Cologne. He was viewed during the time of the council as a reformer, cooperating with theologians like Hans Küng and Edward Schillebeeckx. Ratzinger became an admirer of Karl Rahner, a well-known academic theologian of the Nouvelle théologie and a proponent of Church reform. In 1966, Ratzinger was appointed to a chair in dogmatic theology at the University of Tübingen, where he was a colleague of Hans Küng. In his 1968 book Introduction to Christianity, he wrote that the pope has a duty to hear differing voices within the Church before making a decision, and he downplayed the centrality of the papacy. During this time, he distanced himself from the atmosphere of Tübingen and the Marxist leanings of the student movement of the 1960s that quickly radicalized, in the years 1967 and 1968, culminating in a series of disturbances and riots in April and May 1968. Ratzinger came increasingly to see these and associated developments (such as decreasing respect for authority among his students) as connected to a departure from traditional Catholic teachings. Despite his reformist bent, his views increasingly came to contrast with the liberal ideas gaining currency in theological circles. He was invited by Rev. Theodore Hesburgh to join the theology faculty at the University of Notre Dame, but declined on grounds that his English was not good enough. Some voices, among them Küng, deemed this period in Ratzinger's life a turn towards conservatism, while Ratzinger himself said in a 1993 interview, "I see no break in my views as a theologian [over the years]". Ratzinger continued to defend the work of the Second Vatican Council, including Nostra aetate, the document on respect of other religions, ecumenism, and the declaration of the right to freedom of religion. Later, as the Prefect of the Congregation for the Doctrine of the Faith, Ratzinger most clearly spelled out the Catholic Church's position on