Benedict XVI: his philosophy Long known to the world outside the Holy See as the "Vatican's Rottweiler", German Cardinal Joseph Ratzinger has never been one to hide his rigidly orthodox views.
Dissident theologians, homosexuals, non-Roman Catholics and Muslim countries have all fallen foul of his militantly hard-line, unapologetic Catholic teaching.
In his most recent book, Values in a Time of Upheaval, he condemns gay marriage, divorce, women in the priesthood and genetic manipulation. Those familiar with his track record as Prefect of the Congregation for the Doctrine of the Faith could hardly be surprised by such views.
In an October 1986 Letter to the Bishops of the Catholic Church on the Pastoral Care of Homosexual Persons, for instance, he wrote: "Although the particular inclination of the homosexual person is not a sin, it is a more or less strong tendency ordered towards an intrinsic moral evil; and thus the inclination itself must be seen as objective disorder."
In his role as prefect of the ex-Holy Office from 1981 until the present day, he also played a significant role in stifling theological debate throughout the pontificate of John Paul II.
In particular, people as different as the liberation theologian Brazilian Leonardo Boff in the 1980s, and more recently the Belgian Jesuit Jacques Dupuis, emerged as shattered men after undergoing the Ratzinger disciplinary treatment for their unorthodox views.
Boff was suspected of being too sympathetic to Marxism and, totally discouraged, eventually left the church. Dupuis clashed with the Congregation for the Doctrine of the Faith after the 1997 publication of his book Towards a Christian Theology of Religious Pluralism.
Subjected to a series of cross-examinations by Cardinal Ratzinger's congregation and then suspended from Rome's Gregorian University, Dupuis was so shaken by the ordeal that he ended up in hospital for two weeks.
Those who knew Dupuis well claim that he never fully recovered from the experience of being criticised for allegedly attacking the church he loved and that he died of a broken heart last December.
As someone with a long experience of India and its non-Christian traditions, Dupuis fell foul of Cardinal Ratzinger because his understanding of other religions appeared to clash with that of the Congregation for the Doctrine of the Faith as elaborated in the 2001 document, Dominus Jesus.
That document, largely seen as the brainchild of the new Pope, claims that Christ is the unique saviour and rejects outright the idea that all religions lead to God.
Among other things, Dominus Jesus states: "If it is true that followers of other religions can receive divine grace, it is also certain that objectively speaking they are in a gravely deficient situation."
For many non-Catholics, Dominus Jesus was and is seen as a major stumbling block on the road towards better relations both with other religions and with other Christian churches.
Coherent with his militant, unapologetic espousal of Catholic belief, last August on the eve of John Paul II's visit to Lourdes he told a French newspaper, Le Figaro, that Turkey should not attempt to join the European Union because it is a majority Muslim country with Muslim roots.
"In the course of history, Turkey has always represented a different continent, in permanent contrast to Europe. Making the two continents identical would be a mistake. It would mean a loss of richness, the disappearance of the cultural to the benefit of economics."
True to his beliefs, the new Pope spelt out clearly where he stood and where he thought the Catholic Church should stand only as recently as last Monday, when delivering a typically forthright homily during the Pro Eligendo Papa Mass that preceded the conclave.
He said: "The small boat of thought of many Christians has often been tossed about by these waves - thrown from one extreme to the other: from Marxism to liberalism, even to libertinism; from collectivism to radical individualism; from atheism to a vague religious mysticism; from agnosticism to syncretism . . .
"Every day new sects are created, and what St Paul says about human trickery comes true, with cunning which tries to draw people into error. More and more, we are being dictated to by a [ moral] relativism which accepts nothing as definitive and which takes as its ultimate bench mark the ego and its desires. In contrast, an adult faith is not one that follows the tides and trends of the latest novelties."