What exactly do you mean by "win"? Do the Romans only manage to force out the Persians and restore the status quo? Or do the Romans succeed in actually taking the fight to the Persian heartlands, managing to take Mesopotamia and Armenia?
Actually it depends, as later your PoD is, more restoring the status quo i see like a victory. In any case i think that would be really hard to take Mesopotamia from the persians, the arabs held out some surprise initial victories and managed to occupy Tēsifōn for a while but the sasanians quickly came back to recover the territories. Mesopotamia in all the span of the Sasanian Empire was really hard to take, the romans actually occupied Tēsifōn in 363 but had to retreat.
have heraclius not die in the balkans in 622 , when he was ambushed by the avars, heraclius had just kicked out the Sasanids out of anatolia, the first major defeat for the sassanian forces led under shabaraz , but after Heraclius death in the balkans , the empire fractured in to civil war and it was an easy conquest for shabaraz
Yeah, Heraclius seemed to have the necessary to repel the persians, he kicked out the persians from Anatolia in one campaign and is interesting to think about what Heraclius would do without dying against the Avars.
as the surviving remenant of the byzantine empire fled to the balkans and africa, while the exchart of revena declared himself emperor of the west.
khowrow despite his greatness was a cruel man , maybe if Heraclius survived he could have taken the war effort and defeated the sassanids , but i doudt it would have been a total victory since his empire was faced with numerous years of war .
Talking about Ravenna, i think that without an presence really western-focused the roman lasting in Italy would end sooner, the wars between Ravenna and the Lombards would look pretty different, without the lucky string of ravennese rulers that stabilized post-roman Italy after the collapse of central authority in Constantinople. But one thing that i think would still happen ITTL is the berber conquest of the visigoths, really, someone would conquer it and the berbers were right at the doorstep.
The Avars also cleared the way to a big part of slavic settlement in the balkans, which created some strange communities in Greece. I wonder if the formation of Bulgaria would be butterflied by the roman victory tough, they just kicked the ass of each post-roman state in the region after their arrival.
