The failure of the siege saved the empire from collapse, and, combined with other victories achieved by Emperor Heraclius (r. 610–641) the previous year and in 627, enabled Byzantium to regain its territories and end the destructive Roman–Persian Wars by enforcing a treaty with borders status quo c. 590.

[3] Heraclius started active warfare and personally led his army into the battle, but the situation deteriorated and the Byzantine empire lost all its Near East possessions along with Egypt.

Despite several counter-offensives into Mesopotamia, Heraclius was unable to stop his Persian enemies from laying siege to his capital where from Chalcedon they were able to launch their attack.

[12] Upon hearing the news, Heraclius split his army into three parts; although he judged that the capital was relatively safe, he still sent some reinforcements to Constantinople to boost the morale of the defenders.

Inside the walls, some 12,000 well-trained Byzantine cavalry troops (presumably dismounted) defended the city against the forces of some 80,000 Avars and Sclaveni who were determined to remove all Roman imperial rule over Europe.

[12][13] In thanks for the lifting of the siege and the supposed divine protection of the Virgin Mary, a new proemium for the celebrated Akathist Hymn was written by an unknown author, possibly Patriarch Sergius or George of Pisidia.

[13] Furthermore, after the emperor showed Shahrbaraz intercepted letters from Khosrau ordering the Persian general's death, the latter switched to Heraclius' side.

Still, with the neutralization of Khosrau's most skilled general, Heraclius deprived his enemy of some of his best and most experienced troops, while securing his flanks prior to his invasion of Persia.

Eventually, the Persians were obliged to withdraw all armed forces and return Egypt, the Levant and whatever imperial territories of Mesopotamia and Armenia were in Roman hands at the time of an earlier peace treaty in c. 595.