Well, the Peninsula is divided generally between north and south between Celts/ Germans and Mediterranean peoples, but though the Muslims did take Sicily, and Arabic became the language, not many racial Arabs came, about the same percent as Normans did later on.
Belisaurius and Narsus retook Italy in the 7th Century with German soldiers. The Arabs and Normans came later. Rome had been importing Slavs, Celts and Germans as slaves for a long time.
Not much of the Greco-Romans left.
Ancestry is routinely faked.