 Innis writes that Islam (which he sometimes refers to as Mohammedanism) gathered strength by emphasizing the sacredness of the written word.He notes that the Caliph Iezid II ordered the destruction of pictures in Christian churches within the Umayyad Empire.The banning of icons within churches was also sanctioned by Byzantine Emperor Leo III in 730 while Emperor Constantine V issued a decree in 753–754 condemning image worship.