Leo III the Isaurian or the Syrian (Greek: Λέων Γ΄, Leōn III ), (c. 685–June 18, 741) was Byzantine emperor from 717 until his death in 741. He put an end to a period of instability, successfully defended the empire against the invading Arabs, and adopted the religious policy of Iconoclasm.

Life

Early life

Leo, whose original name was Konon, was born in Germanikeia (Maraş) in the Syrian province of Commagene. His family had been resettled in Thrace, where he entered the service of Emperor Justinian II, when the latter was advancing on Constantinople with an army of 15,000 horsemen provided by Tervel of Bulgaria in 705.

After the victory of Justinian II, Leo was dispatched on a diplomatic mission to Lazica to organize an alliance against the Umayyad Caliphate under Al-Walid I. Leo was appointed commander (stratēgos) of the Anatolic theme by Emperor Anastasios II. On his deposition Leo joined with his colleague Artabasdos, the stratēgos of the Armeniac theme, in conspiring to overthrow the new Emperor Theodosios II.

Siege of Constantinople

Leo entered Constantinople on March 25, 717 and forced the abdication of Theodosios III, becoming emperor as Leo III. The new emperor was immediately forced to attend to the Second Arab siege of Constantinople, which commenced in August of the same year. The Arabs were Ummayad forces send by Caliph Sulayman ibn Abd al-Malik and serving under Maslama. They had taken advantage of the civil discord in the Roman Empire to bring a force of 80,000 men and a massive fleet to the Bosphorus.

Careful preparations and the stubborn resistance put up by Leo wore out the invaders. An important factor in the victory of the Romans was their use of Greek fire. The Arab forces also fell victim to Bulgarian reinforcements arriving to aid the Romans. Leo was allied with the Bulgarians but the chronicler Theophanes the Confessor was uncertain if they were still serving under Tervel or his eventual successor Kormesiy of Bulgaria. Unable to continue the siege in the face of the Bulgarian onslaught and lack of successes, the Arabs were forced to abandon their ambitions on Constantinople in August, 718. Sulayman himself had died the previous year and his successor Umar II would not attempt another siege. The siege had lasted 12 months.

Administration

Having thus preserved the Empire from extinction, Leo proceeded to consolidate its administration, which in the previous years of anarchy had become completely disorganized. In 718 he suppressed a rebellion in Sicily, and in 719 one on behalf of the deposed Emperor Anastasios II. Leo secured the Empire's frontiers by inviting Slavic settlers into the depopulated districts and by restoring the army to efficiency; when the Ummayad Caliphate renewed their invasions in 726 and 739 as part of the campaigns of Hisham ibn Abd al-Malik, the Arab forces were decisively beaten, especially at Akroinon in 740. Leo's military effort was supplemented by his alliances with the Khazars and the Georgians.

Leo undertook a set of civil reforms including the abolition of the system of prepaying taxes which had weighed heavily upon the wealthier proprietors, the elevation of the serfs into a class of free tenants and the remodelling of family and of maritime law. These measures, which were embodied in a new code (the Ecloga) published in 740, met with some opposition on the part of the nobles and higher clergy. The emperor also undertook some reorganization of the theme structure by creating new themes in the Aegean.

Iconoclasm

But Leo's most striking legislative reforms dealt with religious matters, especially iconoclasm. After an apparently successful attempt to enforce the baptism of all Jews and Montanists in the empire (722), he issued a series of edicts against the worship of images (726– - 729). This prohibition of a custom which had undoubtedly given rise to grave abuses seems to have been inspired by a genuine desire to improve public morality, and received the support of the official aristocracy and a section of the clergy. But a majority of the theologians and all the monks opposed these measures with uncompromising hostility, and in the western parts of the empire the people refused to obey the edict.

A revolt which broke out in Greece, mainly on religious grounds, was crushed by the imperial fleet in 727. In 730, Patriarch Germanos I of Constantinople resigned rather than subscribe to an iconoclast decree. Leo had him replaced by Anastasios who willingly sided with the emperor on the question of icons. Thus Leo suppressed the overt opposition of the capital.

In the Italian Peninsula, the defiant attitude of Popes Gregory II and Gregory III on behalf of image-veneration led to a fierce quarrel with the emperor. The former summoned councils in Rome to anathematize and excommunicate the iconoclasts (730, 732); Leo retaliated by transferring Southern Italy and Greece from the papal diocese to that of the Patriarch of Constantinople. The struggle was accompanied by an armed outbreak in the exarchate of Ravenna in 727, which Leo finally endeavoured to subdue by means of a large fleet. But the destruction of the armament by a storm decided the issue against him; his South Italian subjects successfully defied his religious edicts, and the Exarchate of Ravenna became effectively detached from the empire.

Succeeded by: Constantine V