In AD 726, the Byzantine emperor ordered the destruction of all icons, or religious images, throughout the empire, and icons were subject to an imperial ban that was to last, with a brief remission, until AD 843. A defender of icons, St John of Damascus wrote three treatises against those who attack the holy images. He differentiates between the veneration of icons, which is a matter of expressing honor, and idolatry, which is offering worship to something other than God.