While Muslim tradition has glorified and mythified Muhammad over centuries, Western tradition often has been critical towards him. The medieval scholars and churchmen held that Islam was the work of Muhammad who in turn was inspired by Satan. Theories emerged, for example in order to show that Muhammad was the anti-Christ, it was asserted that Muhammad died not in the year 632 but in the year 666 - the number of the Beast.A verbal expression of Christian contempt for Islam was expressed in turning his name from Muhammad to Mahound, the "devil incarnate" Bernard Lewis states that "The development of the concept of Mahound started with considering Muhammad as a kind of demon or false god worshipped with Apollyon and Termangant in an unholy trinity. After the reformation, Muhammad was conceived as a cunning and self-seeking impostor.Such criticisms have become less common over the last two centuries.
http://en.wikipedia.org/wiki/Muhammad