Leo III the Isaurian

Lore & Background

Leo III was born Konon in Germanikeia, a city within the northern boundaries of Syria, east of Cilicia. His native language was Arabic, and the chronicler Theophanes the Confessor later described him as "the Saracen-minded," though direct Islamic influence on him is not well evidenced. The nickname "the Isaurian" is considered a misnomer by most modern scholars; it first appears in Theophanes’s chronicle written around 815 and in the 8th or 9th-century *Parastaseis syntomoi chronikai*, but its origin is disputed—possibly a textual error confusing his hometown with Germanicopolis in Isauria, or a deliberate attempt to delegitimize him as barbaric. He served as a diplomat under Justinian II, traveling to Alania and Lazica to organize an alliance against the Umayyad caliphate, a mission that involved crossing the Caucasus mountains in May with snowshoes and capturing the fortress of Sideron. He later became commander of the Anatolic Theme under Emperor Anastasius II, then conspired with Artabasdos, the commander of the Armeniac Theme, to overthrow Theodosius III. After capturing Theodosius’s son at Nicomedia, he forced the emperor to abdicate and become a monk at Ephesus. Crowned on 25 March 717 by Patriarch Germanus I at Hagia Sophia, Leo immediately faced the second Arab siege of Constantinople, launched by Caliph Sulayman’s forces under Maslama. The siege lasted twelve months, ending in August 718 due to Byzantine use of Greek fire, the impenetrability of Constantinople’s walls, Bulgarian reinforcements, and the Arabs’ exhausted provisions. Leo later suppressed a rebellion in Sicily in 718 and executed the deposed Anastasius II after his failed attempt to retake the throne. He consolidated the empire’s administration, which had been disorganized by the Twenty Years’ Anarchy, and faced yearly Umayyad raids under Caliph Hisham that captured several cities and fortresses, including Dalisandus, Kamachon, Ikonion, Caesarea, and Gangra. A major invading force was destroyed at the Battle of Akroinon in 740. Leo forbade the veneration of icons and invited Slavic settlers into depopulated districts while restoring the army’s efficiency.

Reader's Guide

Leo III's reign marked a turning point for the Byzantine Empire, ending decades of internal chaos and external decline. His successful defense of Constantinople preserved the empire from collapse, while his administrative and military reforms stabilized the frontiers. His iconoclastic edicts (726–729) sparked lasting religious conflict, leading to revolts and the resignation of Patriarch Germanus. The transfer of ecclesiastical authority from Rome to Constantinople in parts of Italy and Illyricum further strained relations with the papacy. His legacy includes the centralization of imperial power and the militarization of the empire, though his iconoclasm remained controversial.

Did You Know?

• Leo III's original name was Konon, and he spoke Arabic as his native language.
• The nickname 'the Isaurian' is considered a misnomer by most modern scholars, possibly a textual error or a delegitimizing label.
• He forced the baptism of all Jews and Montanists in the empire in 722.
• The 740 Constantinople earthquake damaged the Walls of Constantinople, which Leo restored by raising city taxes by 8⅓ percent.