Crusaders imagined Muslims worshipping an idol of Mahomet.

Evidence

The chronicle known as Tudebodus imitatus et continuatus says that Tancred entered the temple, where he saw a huge silver statue of Mahomet enthroned. Comparing the statue to a crucifix, he proclaimed that this was not Christ but Antichrist and ordered his men to destroy it and put the silver to good use, Tudebodus imitatus et continuatus, chap. — John V. Tolan, Saracens, 1702