Joseph Fessio, a theology student of Ratzinger's at the University of Regensburg from 1972-74, and now the English-language publisher of his books.

NPR: Pope Legacy: Teacher Who Returned To Church Roots

In September 2006, Pope Benedict XVI provoked outrage in the Muslim world with a speech given at the University of Regensburg in Germany.

BBC: Pope Benedict XVI in his own words

In the middle of a dense, intellectual, argument about faith and reason, laid out in a speech at Regensburg University in his native Germany, he made reference to a dialogue between a Byzantine ruler, Manuel II Paleologos, and a Persian scholar.

ECONOMIST: Stirring up anger