Siege of Constantinople (674 – 678)
Lasting from 674 to 678, the First Arab Siege of Constantinople was one of the major conflicts in the Byzantine-Arab Wars. Despite a methodically planned attack by the Umayyad Caliphate, the Byzantine Empire was able to defeat their armies with a new technological advance. This victory ensured that the Byzantine state would survive a little longer, as it caused the Arab threat to recede for a while.
After meticulously planned and executed campaigns in 672 and 673, the armies of the Umayyad Caliphate had laid a coastal route of supply bases between Syria and Constantinople. This enabled the Arab navy to build a considerable presence in the eastern Aegean, from which they entered the Sea of Marmara in 674. After capturing territory around Constantinople to build fortified camps for winter, the Umayyad armies dug in for a lengthy siege. A long series of clashes ensued between the Byzantines and the Umayyads, wreaking havoc on the countryside.
At this same time, the Byzantine Empire was under Lombard threat in Italy and Slavic threat on Thessalonica. This crisis point doubtless played a large role in Constantine IV’s choice in late 677- early 678 to confront the Umayyad armies head-on. His fleet, equipped with Greek fire, annihilated the Umayyad fleet during the Battle of Syllaeum. The Umayyad Caliphate was then forced to lift the siege and pay tribute to the Byzantine Empire.
The lifting of this siege had tremendous impact on the sociopolitical world of the day. Having put such a decisive end to the campaign of attrition that the Arab forces had pursued since 661, the Byzantine Empire enjoyed new heights of prestige and respect in the West. Had this nerve center of the Byzantine Empire been captured, the Empire’s far-flung provinces would not have been able to stick together, and would have become easy prey for the Arabs. Instead, the resulting peace gave the Empire a chance to recover its equilibrium after the cataclysmic changes of the preceding decades.