From the Washington Post:
[Pope] Benedict dug up an obscure 14th-century dialogue between a long-forgotten Byzantine Christian emperor, Manuel II Paleologus, and a Persian scholar, about the concept of violence in Islam.
“Show me just what Muhammad brought that was new, and there you will find things only evil and inhuman, such as his command to spread by the sword the faith he preached,” Benedict quoted the emperor as saying to his Islamic interlocutor.
And then Benedict apologized for it.