There is no historical precedent for the worldwide Muslim protests against Danish cartoons since ancient likenesses of Mohammed are on display in museums.

Alan Godlas, who teaches Islamic studies at the University of Georgia, told the Washington Times Islam has long frowned on depictions of the prophet out of a concern any images of Mohammed or other religious figures could lead to idolatry and detract from worship of Allah.

Yet, depictions of Mohammed are in the collections of such institutions as New York's Metropolitan Museum of Art, the Bibliotheque Nationale de France in Paris and the Edinburgh University library.

Mohammed has also been portrayed in the work of revered Muslim artists and of such Western figures as William Blake, Auguste Rodin and Salvador Dali -- as even by the creators of the cable-TV cartoon series South Park, none of which prompted such violence, the newspaper said.

Godlas said timing was a key element in the recent protests.

The reason these cartoons sparked such a reaction has more to do with the tensions that were already there between the Islamic world and the West, he said.