Frontier tribes attempted to enter Roman territory in the mid 2nd century AD but were eventually driven back.
But larger, more aggressive confederacies developed, forcing the Romans temporarily to abandon the Rhine-Danube frontier around 260. In 332 a formerly troublesome Gothic confederacy became Rome's ally against other barbarian groups. Former enemies were similarly used elsewhere.
In 370, the Huns invaded eastern Europe, driving out the Visigoths who wandered aggressively through Europe until 418.
In AD 406 the Rhine froze and barbarians poured into the Western Roman Empire where they settled, the Vandals eventually reaching North Africa.
United in 434 under Attila's brilliant leadership, the Huns from Central Asia terrorized Europe until Attila's sudden death in 453.
By AD 507, the Franks, united by King Clovis, defeated other Germans to become masters of Gaul.
North Sea pirates had long raided Britain but after AD 440 many invaded, rapidly establishing kingdoms in the south and east.
