Phocas was a kentarchos (officer of 100) of the Danubian army. His execution of Maurice after succesfully rebelling in 602 prompted the Persians to 'avenge' Maurice by declaring war. Phocas also increased tribute to the Avars; nonetheless, Slav attacks on Byzantine territority persisted. Discontent resulted in rebellions by the circus factions and generals. The exarch of Carthage rebelled, and a fleet under Heraclius succesfully deposed Phocas, the latwhom was beheaded.

Phocas built a large cistern near the Bronze Tetrapylon and the Church of Forty Martyrs in 609.