| Isaac I Komnenos | |
|---|---|
| Emperor and Autocrat of the Romans | |
.png) Gold tetarteron of Isaac I Komnenos, showing the Emperor wielding a globus cruciger and holding a sheathed sword | |
| Byzantine emperor | |
| Reign | 8 June 1057 – 22 November 1059 |
| Coronation | 1 September 1057 |
| Predecessor | Michael VI |
| Successor | Constantine X |
| Born | c. 1007 |
| Died | 1 June 1060 (aged 53) Monastery of Stoudios, Constantinople (now Istanbul, Turkey) |
| Spouse | Catherine of Bulgaria |
| Issue | Manuel Komnenos Maria Komnene |
| Dynasty | Komnenian |
| Father | Manuel Erotikos Komnenos |
Isaac I Komnenos or Comnenus (Greek: Ἰσαάκιος Κομνηνός, Isaakios Komnēnos; c. 1007 – 1 June 1060) was Byzantine emperor from 1057 to 1059, the first reigning member of the Komnenian dynasty.
The son of the general Manuel Erotikos Komnenos, he was orphaned at an early age, and was raised under the care of Emperor Basil II. He made his name as a successful military commander, serving as commander-in-chief of the eastern armies between c. 1042 and 1054. In 1057 he became the head of a conspiracy of the dissatisfied eastern generals against the newly crowned Michael VI Bringas. Proclaimed emperor by his followers on 8 June 1057, he rallied sufficient military forces to defeat the loyalist army at the Battle of Hades. While Isaac was willing to accept a compromise solution by being appointed Michael's heir, a powerful faction in Constantinople, led by the ambitious Patriarch of Constantinople, Michael Keroularios, pressured Michael to abdicate. After Michael abdicated on 30 August 1057, Isaac was crowned emperor in the Hagia Sophia on 1 September.
As emperor, he rewarded his supporters, but also embarked on a series of fiscal measures designed to shore up revenue and eliminate the excesses allowed to flourish under his predecessors. His aim was to fill the treasury and restore the Byzantine army's effectiveness to preserve the empire. The reduction of salaries, harsh tax measures and confiscation of Church properties aroused much opposition, particularly from Patriarch Keroularios, who had come to think of himself as a king-maker. In November 1058, Keroularios was arrested and exiled, and died before a synod to depose him could be convened.
The eastern frontier held firm during Isaac's reign, Hungarian raids were resolved by a treaty in 1059, while the restive Pechenegs were subdued by Isaac in person in summer 1059. Shortly after, Isaac fell ill, and on the advice and pressure of Michael Psellos, he abdicated his throne in favour of Constantine X Doukas, retiring to the Stoudion monastery where he died later in 1060.