Rome was staging a comeback when the Western half was done in by the Muslims about 650 to 750 AD.
Yeah, I’ve read a couple of studies that show that the roman world remained intact except for the imperial rule until muslims wrecked everthing along on both the north and southern shores of the medeterranian.
The Byzantines and Armenians spent far too much time trying to beat each other, which shows once again that humans prefer the pursuit of dominance more than alliance.