In my Pope Benedict post
It should be noted that at the time of the emperor's dialogue all Islamic expansion had been violent - in Arabia, North Africa, Iberia, Persia, modern-day Iraq, the Levant, Sicily. And in 62 years Constantinople would fall to jihad.
Some may react, "Well the same thing happened under Christianity." Not quite. Christianity began under peaceful private-sector voluntary association; its institutions were later coopted by the State. Islam began as an arm of a state that Mohammed was building. I think it's safe to say that Byzantine emperor Manuel II saw no difference between Mohammed's conquests and his successors' conquests. Would Mohammad have approved of the Caliphate's expansion into the Near East, Africa and Europe after his death?