Al-Walid had pressed the offensive against Byzantium, taking Tyana, the strongest fortress in Cappadocia, and preparing a great expedition against Constantinople itself. No sooner had Sulayman (715-717) succeeded his brother than he undertook to expedite the departure of this expedi- tion under Maslamah, supported by a fleet. Constantinople was blockaded by land and sea in the late summer of 716. Of all the Arab attacks on the capital this was unquestionably the most threatening and the best recorded. The besiegers used naphtha and siege artillery. But the defending emperor, Leo the Isaurian, was a capable and vigorous soldier of humble Syrian origin from Marash. He was probably born a subject of the caliph and knew Arabic as perfectly as Greek. While the besieged were hard pressed, the besiegers were equally harassed. Pestilence, Greek fire, scarcity of provisions and attacks from Bulgars wrought havoc among them. The rigours of an unusually severe winter added their share. Yet Maslamah stubbornly persisted. Neither such hardships nor the death of the caliph seemed to deter him. But the order of the new caliph, Umar ibn-Abd-al- Aziz (717-720), he had to heed. The army withdrew in a pitiful state. The fleet, or what was left of it, was wrecked by a tempest on its way back. The Syrian-born emperor was hailed as the saviour of Christian Europe from Moslem Arabs.
The new caliph, Umar II, was in several respects unique among the Umayyads. His piety, frugality and simplicity contrasted sharply with the luxurious worldliness of his cousins. His ideal was to follow in the footsteps of his maternal grandfather, the second orthodox caliph, whose namesake he was. During his brief reign the theologians had their day. Hence the saintly reputation he acquired in Moslem history. Umar abolished the practice introduced by Muawiyah of cursing Ali from the pulpit at the Friday prayers. He introduced fiscal reforms which failed of survival because they lowered the revenue collected from
