Before it fell for good to the Ottomans in 1453, the city of Constantinople withstood something like a dozen sieges by foreign armies over its long history. The one successful siege, by the soldiers of the Fourth Crusade in 1204, was of course eventually rolled back when the Latin Empire went defunct in 1261. But other than that, all of them prior to 1453 were unsuccessful. Arab armies under the Umayyad Caliphate attempted two of those failed sieges. The first may have been made in 674-678 (this is generally considered the Arabs’ “first siege” of Constantinople, though it wasn’t really as cohesive as that description implies), when the Byzantines may have been saved by the advent of Greek Fire and its use in destroying an Arab naval blockade. The second probably began on this date in 717 and ended on this date in 718, and was the last time the caliphate really threatened the city.