What caused the liberation of the byzantium from the Persians?

The liberation of Byzantium from Persian control in the early 7th century was primarily due to the decline of the Sasanian Empire, which faced internal strife and external pressures. The Byzantine Empire, under Emperor Heraclius, launched a series of military campaigns that effectively pushed back Persian forces and regained lost territories. Additionally, the strategic alliances and support from local populations played a crucial role in facilitating the Byzantine resurgence. Ultimately, the combination of effective military strategy and the weakening of Persian power led to the liberation of Byzantium.