Samir Khalil Samir, S.J., writes:

In the speech Pope was trying to show how western society—including the Church—has become secularised by removing from the concept of Reason its spiritual dimension and origins which are in God. In early Western history, Reason was not opposed to faith, according to the Pope, but instead fed on it.

During the speech Benedict XVI quoted from a recent book by Prof Theodore Khoury, an expert on Byzantium, who has reprinted the text of a late Middle Ages dialogue between a Byzantine emperor, Manuel II Paleologus, and a Persian Muslim.

The Holy Father chose this text because it contained a “key sentence” in which the emperor criticises the Muslim for Islam’s violence as exemplified by the command to spread the faith by the sword. No historian can deny the fact that Muhammad and, after him, the caliphs often used violence to convert conquered peoples. This does not mean that Muhammad liked violence but it does mean that he was a man of his time. Fighting among Arab tribes was widespread, including over grazing land.

The first biography of Muhammad written by a Muslim was titled “Book of [Military] Campaigns” (the term is Maghāzī which has been transliterated as razzias).

Certainly, one can criticise Emperor Manuel for Islam did not spread by violence alone. In Indonesia, Malaysia and some African countries Islam was brought by Muslim traders. In other countries it arrived via Sufi mystics (who could also be warriors as was the case in Morocco).  

But for the emperor, “violence is something unreasonable [. . .] incompatible with the nature of God and the nature of the soul”. It is this sentence that got the Pope’s attention, so much so that he repeated it five times.

Basically then, the message is that anyone who engages in violence ceases being a believer; anyone, Christian or Muslim, who goes along with violence goes against Reason and God, whose is the source of Reason.

Full article here.