From Reuters:

Born in Bavaria on April 16, 1927, Ratzinger was a leading theology professor and then archbishop of Munich before taking over the Congregation for the Doctrine of the Faith in 1981.

In that office, Ratzinger disciplined Latin American "liberation theology" theologians, denounced homosexuality and gay marriage and pressured Asian priests who saw non-Christian religions as part of God's plan for humanity.

In a document in 2000, he branded other Christian churches as deficient -- shocking Anglicans, Lutherans and other Protestants in ecumenical dialogue with Rome for years.

As dean of the College of Cardinals, he presided over John Paul's funeral Mass and the daily meetings of cardinals to discuss the next papacy.

Ratzinger was the oldest cardinal to be named pope since Clement XII, who was also 78 when he became pope in 1730. He is the first German pope since Victor II (1055-1057).