Initially serving under Heraclius, the contingent of Armenian troops under his command were instrumental in the Byzantine success against the Sassanids during the Byzantine-Persian Wars that culminated in the overthrow of Khosrau II in 628.
[1] He also served as the sparapet (commander in chief) of Byzantine Armenia from about 630 to 638, and during this time may have been responsible for the founding of the Cathedral of Mren.
He was succeeded in this position by David Saharuni, from the middle-ranking Armenian nobility, after the latter was accused of plotting against the life of Heraclius.
While being sent into exile, David escaped and made his way back to Armenia.
Evidence of this chronicled by Bishop Sebeos of the Bagratunis, such as "41:16 Also involved in that plot was Dawit’ Sahaṙuni, whom Mzhēzh arrested and sent to the palace.