The fall of Alexandria, the capital of Roman Egypt, marked the first and most important stage in the Sasanian campaign to conquer this rich province, which eventually fell completely under Persian rule within a couple of years.

[3] The Persian shah, Khosrow II, had taken advantage of the internal turmoil of the Byzantine Empire after the overthrow of Emperor Maurice by Phocas to attack the Roman provinces in the East.

[4] The Persian invasion of Egypt began either in 617 or 618, but little is known about the details of this campaign, since the province was practically cut off from the remaining Roman territories.

[5] The Persian army headed for Alexandria, where Nicetas, Heraclius' cousin and local governor, was unable to offer effective resistance.

[2] As the Roman emperor, Heraclius, reversed the tide and defeated Khosrow, Shahrbaraz was ordered to evacuate the province, but refused.