When both the Visigoths and Ostrogoths were attacked by the Huns in 370, the Visigoths fared better, many of them fleeing into a Roman province. In 378 the Visigoths rebelled against the Roman authorities. On horseback, they fought the battle of Adrianople (in present-day Turkey), destroying a Roman army and killing Rome’s eastern emperor, Valens (c. 328–378). The Visigoths’ introduction of the cavalry (troops trained to fight on horseback) as part of warfare determined European military, social, and political development for the next thousand years.

After the battle of Adrianople, the Visigoths moved into Italy, and under the leadership of their ruler, Alaric (c. 370–410), sacked Rome in 410, an event that signaled the beginning of the decline of the Roman Empire. After the success of the Visigoths, one tribe after another invaded the empire.

The Visigoths continued westward into Gaul, and there set up a monarchy that consisted of much of France and Spain and was centered in Toulouse. But in 507 they were driven out by the Franks, and the Visigoths withdrew into the Iberian Peninsula (present-day Spain and Portugal). Toledo was established as the capital of the Visigoth kingdom in 534. Roderick (or Rodrigo), the last of the Visigoth kings in Spain, was defeated and killed in 711 during a battle with the Muslims (Moors), who invaded from northern Africa. The Muslims went on to rule most of the Iberian Peninsula until the mid-1400s.