The Siege of Constantinople in 626 by the Avars, aided by large numbers of allied Slavs and the Sassanid Persians, ends in a strategic victory for the Byzantines.

The failure of the siege saves the Empire from collapse, and, combined with other victories achieved by Emperor Heraclius (r. 610–641) the previous year and in 627, enables Byzantium to regain her territories and end the destructive Roman-Persian Wars by enforcing a favorable treaty with borders status quo circa 590.