Constantine IV - The Siege of Constantinople: 674-678

The Siege of Constantinople: 674-678

Then, commencing in 674, the Arabs launched the long awaited siege of Constantinople. The great fleet that had been assembled set sail under the command of Abdu'l-Rahman ibn Abu Bakr before the end of the year; and during the winter months some of the ships anchored at Smyrna, the rest off the coast of Cilicia. Additional squadrons reinforced the forces of Abd ar-Rahman before they proceeded to the Hellespont, into which they sailed in about April 674. From April to September 674 the fleet lay moored from the promontory of Hebdomon, on the Propontis, as far as the promontory of Kyklobion, near the Golden Gate, and throughout those months continued to engage with the Byzantine fleet which defended the harbour continued from morning to evening.

Knowing that it was only a matter of time before Constantinople was under siege, Constantine had ensured that the city was well provisioned. He also constructed a large number of fireships and fast-sailing boats provided with tubes or siphons for squirting fire. This is the first known use of Greek fire in combat, which was one of the key advantages that the Byzantines possessed. In September, the Arabs having failed in their attempts to take the city, sailed to Cyzicus, which they made their winter quarters. Over the following five years, the Arabs would return each spring to continue the siege of Constantinople, but with the same results. The city survived and finally in 678, the Arabs were forced to raise the siege. The Arabs withdrew, and were almost simultaneously defeated on land in Lycia in Anatolia. This unexpected reverse forced Muawiyah I to seek a truce with Constantine. The terms of the concluded truce required the Arabs to evacuating those islands in the Aegean they had seized, as well as an annual tribute to the Emperor consisting of fifty slaves, fifty horses and 3,000 pounds of gold. The raising of the siege allowed Constantine to go to the relief of Thessalonika, still under siege from the Slavs.