During Hadrian's time the "barbarians" they were fighting were Picts from Scotland. The Anglo-Saxons didn't come over until after the Romans left and (accordin

During Hadrian's time the "barbarians" they were fighting were Picts from Scotland. The Anglo-Saxons didn't come over until after the Romans left and (according to legend) King Vortigern needed mercenaries to fight his fellow Romano-Celts and be his enforcers. Also... this wouldn't be the only time that Anglo-Saxons would be working for the Eastern Roman Empire. They were also a fairly substantial fraction of the Varangian Guard, particularly after the Normans conquered Britain. Somewhere along the way a lot of them wound up settling in what's now the Ukraine, but I don't know what happened to those.