Constantine IV
Constantine IV saved Constantinople from the first Arab siege and settled the Christological quarrel that had divided the empire for two centuries. Born around 652, he was the son of Constans II, who had moved the imperial residence to Sicily and was murdered in his bath at Syracuse in 668. Constantine put down the usurper who followed and returned the centre of the empire to Constantinople. The Arab siege ran from about 674 to 678 — a sustained naval blockade and repeated assaults by the Umayyad fleet, in the first serious attempt to take the city. What broke it was Greek fire: a petroleum-based incendiary, projected under pressure through siphons mounted on ships, which burned on water and could not be put out. Its composition was a state secret so well kept that it has never been reconstructed with certainty. The Arab fleet was destroyed, the withdrawal cost them more ships in a storm, and Mu'awiya agreed a thirty-year peace with tribute. Constantine then called the Sixth Ecumenical Council at Constantinople in 680, which condemned monothelitism — the compromise doctrine of a single will in Christ that his grandfather Heraclius had promoted to reconcile the eastern provinces, and which had failed to reconcile anyone and was now irrelevant because those provinces were lost. He presided over its sessions in person. He also recognised a Bulgar state south of the Danube by treaty in 681 after losing a campaign to Asparuh, and paid tribute for it. He died of dysentery in 685 at about thirty-three.
- Lived: 652 CE – 685 CE
- Nationality: Byzantine
- Roles: emperor, head_of_state, military_leader
