[3] The Exarch's son, Heraclius the Younger, was the rebellion's candidate to replace Phocas, and with a fleet sailed directly for the imperial capital, Constantinople, which he seized on 5 October 610.
[5][6] Nicetas' cause was aided by dissatisfied factions within Egypt itself, including the former prefect of Alexandria Theodore and his sons, probably the very wealthy and powerful Egyptian family of the Apiones, and even by prophecies and portents spread by holy men who opposed Phocas' tyranny.
According to the account of John of Nikiu, the prefect of the Mareotis was bribed to switch sides, and in a battle before Alexandria, Nicetas' forces defeated and killed Phocas' general.
[8] Bonakis was then dispatched to complete the conquest of the Nile Delta, but two garrisons, at Semanub and Athrib, resisted until Phocas sent a general, Bonosus, from Palestine to recover Egypt.
[12] As Walter Kaegi comments, in view of the mutual trust between Nicetas and Heraclius, this made eminent sense, since Egypt contributed some 30% of the praetorian prefecture of the East's annual income, and the new regime "would not have wished some other politically ambitious figure to stir up new unrest there as they had recently done themselves".
[12][13] Later, in 615 or 616, he helped reconcile the Monophysite churches of Alexandria and Antioch, but it is unclear whether Nicetas remained continuously in office; at any rate, he was absent from Egypt for several extended periods.
[a] Heraclius reportedly left control of the capital to Nicetas when he went to Cappadocia to meet Priscus, who was besieging the Sassanid Persians in Caesarea.
Nicetas' role in preparing for and during the defence of the province, as well as the detailed course of the invasion, are unknown, but both he and Patriarch John fled Alexandria for Cyprus and then Rhodes, shortly before its fall to the Persians.