Leo III seized Byzantium's throne months before a vast Arab siege
In March 717 an Arabic-speaking general named Konon was crowned emperor as Leo III. By August an Umayyad army of perhaps 80,000 to 150,000 men and a huge fleet had reached Constantinople. The walls, Greek fire and Bulgarian allies held for twelve months, and Leo later set off the long quarrel over holy images.
Born around 685 in Germanikeia, north of Syria, Konon spoke Arabic as his native language; the chronicler Theophanes called him Saracen-minded, though there is little sign Islam shaped him. The label the Isaurian is itself probably a misnomer, perhaps a copying mistake about his hometown or a slur meant to cast him as a barbarian. Under Justinian II he was sent on a mission to the Caucasus and, left stranded without funds, came back across the mountains on snowshoes. As commander of the Anatolic Theme he joined Artabasdos, head of the neighbouring Armeniac Theme, in a revolt, forced Theodosius III to abdicate and become a monk, and was crowned in Hagia Sophia on 25 March 717, ending two decades of turmoil known as the Twenty Years' Anarchy.
The second Arab siege of Constantinople followed immediately, led by Maslama, brother of Caliph Sulayman. Defensive preparations begun under Anastasius II, Leo's stubborn resistance, Greek fire and Bulgarian attacks on the besiegers wore them down, and in August 718, their supplies exhausted, they withdrew. Sulayman's successor Umar II never tried again. Raids into Asia Minor continued for years, but Leo reorganised the army, settled Slavs in emptied districts and allied with the Khazars and Georgians.
He also tightened central control over the Church. He redirected about 350 pounds of gold a year in Sicilian revenues from the papacy to the imperial treasury and moved several western bishoprics under Constantinople's authority. After the 740 earthquake damaged the city walls, he raised taxes to repair them.
His most lasting act was religious. Between 726 and 729 he issued edicts against venerating images, beginning Byzantine iconoclasm. Patriarch Germanus resigned rather than comply, John of Damascus wrote against him, and popes Gregory II and III resisted, though some historians think tax disputes drove the Italian unrest as much as icons. Motives are debated, from eastern suspicion of images to interaction with Islamic attitudes. Leo died of dropsy on 18 June 741.
Source: Leo III the Isaurian
