WThe Byzantine Empire was ruled by the Isaurian or Syrian dynasty from 717 to 802. The Isaurian emperors were successful in defending and consolidating the Empire against the Caliphate after the onslaught of the early Muslim conquests, but were less successful in Europe, where they suffered setbacks against the Bulgars, had to give up the Exarchate of Ravenna, and lost influence over Italy and the Papacy to the growing power of the Franks.
WArtavasdos or Artabasdos, Latinized as Artabasdus, was a Byzantine general of Armenian descent who seized the throne from June 741 or 742 until November 743. His reign constitutes a usurpation against Constantine V, who had retained control of several themes in Asia Minor.
WConstantine V was Byzantine emperor from 741 to 775. His reign saw a consolidation of Byzantine security from external threats. As an able military leader, Constantine took advantage of civil war in the Muslim world to make limited offensives on the Arab frontier. With this eastern frontier secure, he undertook repeated campaigns against the Bulgars in the Balkans. His military activity, and policy of settling Christian populations from the Arab frontier in Thrace, made Byzantium's hold on its Balkan territories more secure. Religious strife and controversy was a prominent feature of his reign. His fervent support of Iconoclasm and opposition to monasticism led to his vilification by later Byzantine historians and writers, who denigrated him as Kopronymos or Copronymus (Κοπρώνυμος), meaning the dung-named.
WConstantine VI was Byzantine Emperor from 780 to 797. The only child of Emperor Leo IV, Constantine was named co-emperor with him at the age of five in 776 and succeeded him as sole Emperor in 780, aged nine. His mother Irene exercised control over him as regent until 790, assisted by her chief minister Staurakios, and eventually Constantine ruled himself, But his reign alone was short-lived, as he returned the position empress to his mother again in 792, and eventually his mother blinded and deposed him.
WIrene of Athens, surnamed Sarantapechaina (Σαρανταπήχαινα), was Byzantine empress consort by marriage to Emperor Leo IV from 775 to 780, regent during the minority of her son Constantine VI from 780 until 790, co-regent from 792 until 797, and finally sole ruler and first empress regnant of the Byzantine Empire from 797 to 802. A member of the politically prominent Sarantapechos family, she was selected as Leo IV's bride for unknown reasons in 768. Even though her husband was an iconoclast, she harbored iconophile sympathies. During her rule as regent, she called the Second Council of Nicaea in 787, which condemned iconoclasm as heretical and brought an end to the first iconoclast period (730–787).
WLeo III the Isaurian, also known as the Syrian, was Byzantine Emperor from 717 until his death in 741 and founder of the Isaurian dynasty. He put an end to the Twenty Years' Anarchy, a period of great instability in the Byzantine Empire between 695 and 717, marked by the rapid succession of several emperors to the throne. He also successfully defended the Empire against the invading Umayyads and forbade the veneration of icons.
WLeo IV the Khazar was Byzantine Emperor from 775 to 780 AD. He was born to Emperor Constantine V and Empress Tzitzak in 750. He was elevated to Caesar the next year, in 751, and married to Irene of Athens in 768. When Constantine V died in September 775, while campaigning against the Bulgarians, Leo IV became senior emperor on 14 September 775. In 778 Leo raided Abbasid Syria, decisively defeating the Abbasid army outside of Germanicia. Leo died on 8 September 780, of tuberculosis. He was meant to be succeeded by his son Constantine VI, but rule instead transferred to his wife Irene, who assumed the role of regent and later empress.