The Iberian Peninsula has a wide coastal plain facing the Atlantic Ocean sloping up to central plateau and some mountains. To the north, it’s very mountainous. Three major river systems come out of the central hills, draining into the Atlantic. Along the Mediterranean-facing coast, the land slopes up to the plateau quickly, leaving only a narrow coastal plain margin. This coast is crowded with fishing and shipping ports and has always been an integral part of the Mediterranean world. But the plateau tends to be dry, often with thinner soil. It’s good for sheep but not really good for serious farming. The people there have generally been poorer than along the coast. Although the plateau is all part of modern Spain, in the past it has rarely been unified. It tends to be territory that is fought over—and in the Middle Ages, it certainly was.
Before the Arab invasion, Spain was a patchwork of kingdoms made up of native people, Latin immigrants, and Visigothic conquerors. There were the Basques, and there may have been other native people. The generally spoken language was a form of Latin, but the ruling class were Germanic-speaking Visigoths. They had also adopted a form of Christian faith that was Arian, not accepted by the orthodox Christians of Rome and Constantinople. Around the time of Muhammad’s birth, the ruling Visigoths formally joined the Roman theology already followed by their peasants.
The Visigothic kingdom was weak around 710, when the Arabs were looking across from Africa and wondering if it was time to cross. King Roderigo was not the previous king’s son, so he could not draw on a unified military base. Left alone, they’d have had civil war. This was not atypical. Like many other Germanic peoples, they had originally elected kings, and their system in the 7th century was a blend of birth and election that was suited to succession disputes in every generation. This meant the aristocracy was riddled with people who believed their family should have ruled at some point.
Visigothic law tended to be harsh. Blending it with Roman law and 6th century Roman theology, one result was that the law code of 654 was severely anti-Jewish. Passover was banned, as were other holidays. Circumcision was punished by mutilation of the adult doing it. Jewish marriage and burial rites were banned, and following a kosher diet was illegal. Spain had a large Jewish population, since as an outlying Roman colony it had welcomed the Jewish diaspora when they were evicted from Israel. The Jews were probably a majority of the skilled craftsmen, too. So they had no reason to be loyal to the Visigoths.
We don’t have detailed information about how the Arabs conquered most of the peninsula in five years, between 711 and 715. The crossing expedition was led by Tariq ibn Ziyad, who was probably a converted Berber or the son of a mixed Arab-Berber union. His army included Arabs, but its numbers came from the Berbers who had adopted Islam. One problem with using newly conquered loot to pay your army is that you always need new conquests. The Berbers were eager to get a piece of the conquerors’ privilege.
Tariq’s forces landed on Gibraltar and set it up as a base. Its name “Gibraltar” began as “Jabal Tariq,” the mountain of Tariq. Then they crossed to mainland Spain, and at some point, maybe a month later, King Roderigo met them with his knights. But a block of the knights secretly committed to standing back in the battle so that the king would be slain. The battle was a bloodbath and ended organized Visigothic resistance to the invasion. Tariq sent part of his army to secure the city of Cordoba, while he turned toward Toledo.
The Umayyad governor of Ifriqiyah, Musa ibn Nusayr, oversaw and later joined the expedition. He was a freed slave of the Governor of Egypt, and he became an independent governor due to the vast territory added under his rule. In 712, he too crossed into Spain and conquered Seville. Sometimes meeting to coordinate and fight over treasures, Tariq and Musa wiped out the rest of the Visigothic resistance in every region of Spain except the far north. There, neighboring the Basques, a Visigoth set up the Kingdom of Asturias. In 717, he successfully defended the small mountain kingdom against a Muslim army.
The Muslims called their new land al-Andalus and began minting gold dinars by 716, perhaps recycling gold treasures taken from houses and churches. The earliest of these coins says “There is no God but God”—in Latin. They didn’t set up garrison cities, as the earlier Arab conquests had done. Perhaps the majority Berber men were unwilling to live in towns of any kind. Arabs settled in the cities, Berbers in the country, and all married local women.
Musa appointed two of his sons to rule Andalusia (as we usually call it) and Ifriqiyah when he and Tariq were ordered to report back to Damascus, bringing treasure. His son Abd al-Aziz in Andalusia married the dead king’s widow and went on with the conquest project, taking in the rest of modern Portugal. But his Visigothic wife encouraged him to behave and dress as a king, and this didn’t sit well with the Arab-Berber army. Perhaps on the Caliph’s orders, perhaps on their own, they executed him. His head was sent to Damascus while his father Musa was still there. Musa and Tariq never returned to Andalusia.