John Mansur, working in Islamic Syria, thought he could safely criticise the Roman Emperor for meddling in Christian worship. But he was wrong.
In 726, the Roman Emperor Leo III, seated in Constantinople (modern Istanbul), declared that images of Christ and his saints were ‘idolatrous’ and must be scrubbed from all church walls. The ban was sternly enforced, but there were rebels; and the outspoken John Mansur encouraged them with stirring pamphlets written from the safety of the Islamic court of Hisham ibn Abd al-Malik, Caliph of Damascus.