When the Roman Empire was split into two, Hispania became part of the West Roman Empire. Around 400 AD, the Germanic Suevi and Vandals began plundering neighboring Gaul and eventually invaded Hispania. The Suevi established a kingdom in what is today modern Galicia and northern Portugal while the Vandals took over Gallaecia. The Silingi Vandals occupied the region that still bears a form of their name –Vandalusia, modern Andalusia, in Spain. The Byzantines established an enclave, Spania, in the south, with the intention of reviving the Roman Empire throughout Iberia. Eventually, however, Hispania was reunited under Visigothic rule.
In the 8th century, Muslim Moors from North Africa invaded and conquered most of the Iberian Peninsula. Under Islamic law, Christians and Jews, although permitted to continue to practice their religions were essentially made second-class citizens and were subjected to special taxes and discrimination.
The Muslim community in the Iberian Peninsula was itself diverse and beset by social tensions. The Berber people of North Africa, who had provided the bulk of the invading armies, clashed with the Arab leadership from the Middle East. Over time, large Moorish populations became established, especially in the Guadalquivir River valley, the coastal plain of Valencia, the Ebro River valley and (towards the end of this period) in the mountainous region of Granada.
Córdoba, the capital of the caliphate, was the largest, richest and most sophisticated city in Western Europe. Mediterranean trade and cultural exchange flourished. Muslims imported a rich intellectual tradition from the Middle East and North Africa. Muslim and Jewish scholars played an important part in reviving and expanding classical Greek learning in Western Europe. The Romanized cultures of the Iberian Peninsula interacted with Muslim and Jewish cultures in complex ways, thus giving the region a distinctive culture. Outside the cities, where the vast majority lived, the land ownership system from Roman times remained largely intact since Muslim leaders rarely dispossessed landowners, and the introduction of new crops and techniques led to an expansion of agriculture.
In the 11th century, the Muslim holdings fractured into rival Taifa kingdoms, allowing the small Christian states the opportunity to greatly enlarge their territories. The arrival from North Africa of the Islamic ruling sects of the Almoravids and the Almohads restored unity upon the Muslim holdings, with a stricter, less tolerant application of Islam, and saw a revival in Muslim fortunes. This re-united Islamic state experienced more than a century of successes that partially reversed Christian gains.