1. Historical context
The reign of Phokas (602-610) had dire consequences on Byzantium. The empire faced many problems due to the conflicts in the interior and the war declared on the Byzantines by Persian king Chosroes II (591-628), using the assassination of emperor Maurice by Phokas as a pretext. The reign of Phokas ended on 5 October 610. Herakleios, the son of the commander of the (province) of Byzantine Africa Herakleios, who had already rebelled against Phokas since 608, entered Constantinople as the leader of the rebel army.
Just before Herakleios entering Constantinople, the people of the city had also rebelled. The rebellious citizens and members of the demoi (parties) arrested Phokas and took him to Herakleios who had just entered Constantinople. Herakleios ordered the execution of Phokas by decapitation. His corpse was drawn by the mob along the Mese. On the same day, Domentziolos, the brother of Phokas, and other officials of the regime were also executed.
During that time, (patrician) Komentiolus, the second brother of Phokas, was in Ankara. He was the leader of the troops fighting the Persians in eastern Asia Minor and had led his army to Ankara for the winter. It is possible that he had chosen Ankara instead of Caesarea of Cappadocia (which was the base of the military operations of the Byzantines on the eastern border) due to its proximity to Constantinople. It is also possible that Phokas had ordered his brother to be at hand in order to help him against the troops of Herakleios.1 When the news about the death of Phokas and his associates reached Ankara, Komentiolos was afraid that he would also become a victim of the new regime. That reason, along with his desire to avenge the death of his two brothers and the prospect to ascend on the throne as the sole surviving relative of the former emperor if he succeeded, led him to the rebellion against Herakleios.
2. The rebellion of Komentiolos and its suppression
At the end of October or the beginning of November 610, patrikios Komentiolus, the brother of former emperor Phokas, rebelled against emperor Herakleios in Ankara of Galatia. He was the leader of the army fighting the Persians in eastern Asia Minor and held the rank of (military commander of the East). He had led his troops to Ankara for the winter, during which no military operations were conducted. Komentiolos occupied a large part of Asia Minor up to the borders of Bithynia.2
When the news about the rebellion reached Constantinople, Herakleios sent monk Herodianus to Ankara in order to negotiate with Komentiolos. The mission of Herodianus was unsuccessful and the emperor sent a second negotiator, monk Philippikos, who was a former general of emperor Maurice. Philippikos advanced to Noumerika of Bithynia but he was arrested by the troops of Komentiolos.
Theodore of Sykeon, who was later proclaimed saint, is associated with these events. His Life is the only source on the rebellion of Komentiolos. It seems that Theodore, bishop of Anastasioupolis and known for his piety all over the of Galatia, played a role in the events.3 It is not known whether his negative attitude towards the rebellion of Komentiolos was real or invented by the author of his biography. When Komentiolos, however, decided to execute Philippikos and other prisoners in Ankara, (most glorious) Eutychianus and other important prisoners sent a letter to Theodore, begging him to save them. It is possible that the influence of the hierarch extended to secular issues as well.
His intervention, however, was not needed. At the end of the winter of 611, just before Komentiolos executing the prisoners and marching against Herakleios to Constantinople, the rebellion ended with the intervention of Justin, “πατρίκιος των Αρμενίων” (patrikios of the Armenians) or (military commander of Armenia). Justin attacked at night, released the prisoners and killed Komentiolos.
The assassination of Komentiolos by the troops of Justin and the suppression of the rebellion had political consequences. Komentiolos was the last surviving brother of Phokas and none of the male relatives of the former emperor had survived,4 a fact which suited Herakleios, who did not have to face a contender to the throne.
Apart from the direct consequences on the people involved, the rebellion of Komentiolus had great consequences on the Byzantine Empire as a whole. In order to be in a position to help his brother in Constantinople, Komentiolus chose to camp in Ankara of Galatia for the winter. The camping of the troops of Komentiolos in Ankara instead of Caesarea of Kappadokia left the border undefended. The Persians took advantage of the weak point in the defence of the Byzantines. In 611, following the suppression of the rebellion of Komentiolus, they invaded the Byzantine lands of Asia Minor and conquered Caesarea.
The turmoil caused by the occupation of a large part of Asia Minor by Komentiolos had even greater consequences. The civil war prevented Herakleios from negotiating with the Persians when needed. It also prevented him from defending the eastern provinces of the state, most particularly Syria, Palestine and Egypt. During the next few years, starting from 613, the Persian invaders conquered these provinces and occupied them until 629.