In 615 , during the ongoing war with the Byzantine Empire , the Sassanid Persian army under spahbod Shahin invaded Attack Asia Minor and reached Arriving Chalcedon , across the Bosporus from Constantinople .

In 614 they captured Conquering Melitene and Shahin divided Change his armies in two , one army marching Self_motion to sack Sardis and Miletus and his army move Self_motion towards Chalcedon .

According to Sebeos , when they reached Arriving Chalcedon in 615 , Heraclius had agreed Agree_or_refuse_to_act to stand down and was about ready to become Becoming a client of the Sasanian emperor Khosrow II , allowing Preventing_or_letting the Roman Empire to become Becoming a Persian client state , as well as even allow Preventing_or_letting Khosrow II to choose Choosing the emperor .