What if Khosrau II defeated the Byzantines. Say that the POD is Heraclius (the younger) being killed in Africa just as he was about to set sail for Constantinople. Since it was unlikely anybody else could have saved Byzantium, how would the rest of the war play out? When would Constantinople fall and what would Heraclius the Elder and his nephew do? When peace is made, what would be the fate of the empire's remnants? Finally, how would the Sassanids develop now that they have seized the entirety of Byzantine Asia? Will they enter a golden age or will they collapse in on themselves?