Heraclius the Elder in the context of "Heraclius I"

Heraclius (Greek: Ἡράκλειος, romanized: Hērákleios; c. 575 – 11 February 641) was Byzantine emperor from 610 to 641. His rise to power began in 608, when he and his father, Heraclius the Elder, the Exarch of Africa, led a revolt against the unpopular emperor Phocas.

Heraclius's reign was marked by several military campaigns. The year Heraclius came to power, the empire was threatened on multiple frontiers. Heraclius immediately took charge of the Byzantine–Sasanian War of 602–628. The first battles of the campaign ended in defeat for the Byzantines; the Persian army fought their way to the Bosphorus but Constantinople was protected by impenetrable walls and a strong navy, and Heraclius was able to avoid total defeat. Soon after, he initiated reforms to rebuild and strengthen the military. Heraclius drove the Persians out of Asia Minor and pushed deep into their territory, defeating them decisively in 627 at the Battle of Nineveh. The Persian Shah Khosrow II was overthrown and executed by his son Kavad II, who soon sued for a peace treaty, agreeing to withdraw from all occupied territory. This way peaceful relations were restored to the two deeply strained empires.

Phocas (Latin: Focas; Ancient Greek: Φωκάς, romanized: Phōkás; 547 – 5 October 610) was Eastern Roman emperor from 602 to 610. Initially a middle-ranking officer in the Roman army, Phocas rose to prominence as a spokesman for dissatisfied soldiers in their disputes with the court of the Emperor Maurice. When the army rebelled in 602, Phocas emerged as the leader of the mutiny. The revolt led to the overthrow and execution of Maurice in November 602.

Phocas deeply mistrusted the uncooperative elite of Constantinople, to whom he was a usurper and a provincial boor. He therefore attempted to base his regime on relatives installed in high military and administrative positions. He immediately faced challenges in domestic and foreign affairs, and responded with little success. He dealt with domestic opposition with increasing ruthlessness that alienated ever wider circles, including some of his own household. The Sasanian Empire launched a massive invasion of the eastern provinces. Finally, the exarch of Africa, Heraclius the Elder, rebelled against Phocas and gained wide support throughout the empire. Phocas attempted to use border troops to crush the rebellion, but this only resulted in allowing invaders to break into the heartlands of the Empire. Heraclius the Elder's son, Heraclius, took Constantinople on 5 October 610, executed Phocas the same day, and declared himself emperor.