Siege of Constantinople

The counter-attack launched by Heraclius took on the character of a holy war, and an acheiropoietos image of Christ was carried as a military standard (similarly, when Constantinople was saved from a combined Avar–Sassanid–Slavic siege in 626, the victory was attributed to the icons of the Virgin that were led in procession by Patriarch Sergius about the walls of the city). In this very siege of Constantinople of the year 626, amidst the climactic Byzantine–Sasanian War of 602–628, the combined Avar, Sassanid, and Slavic forces unsuccessfully besieged the Byzantine capital between June and July. After this, the Sassanid army was forced to withdraw to Anatolia. The loss came just after news had reached them of yet another Byzantine victory, where Heraclius's brother Theodore scored well against the Persian general Shahin. Following this, Heraclius led an invasion into Sassanid Mesopotamia once again.