In 711 AD, the Muslim governor of Tangiers, backed by a Berber army, crossed the Strait of Gibraltar and invaded Christian southern Iberian Peninsula(Spain and Portugal). The conquering of the Christians was fairly swift. By July of 711AD, they had already destroyed the ruling Visigoth army that was led by King Roderic. After defeating Roderic, the Muslim armies went on to capture Cordoba, and the Visigoth capital of Toledo. The next year Muslim armies captured Seville and Merida. Then by 720AD, the entire peninsula was under Muslim control and they were marching deep into southern France.
The Muslims renamed the Iberian Peninsula, calling it Al-Andalus. Al-Landaus would be ruled by a succession of governors. Most were only permitted to serve for one or two years, and all were under the ultimate control of the Umayyad caliph(religious leader) in Damascus (Lebanon). Muslim settlement on the peninsula was done according to ethnic or tribal lineage. The emergence of Islamic(Muslim) society was slow. The majority of the population was still Christian, and both the Christians and the Jews were protected by law. Over time, much of the Christian population in certain cities converted to the Muslim religion. However, during the next two centuries the northern peninsula would become increasingly populated with Christians. At the time, they desperately wanted to restore what they called Christian Iberia.
After awhile, the papacy in Rome began taking a closer look at Iberian affairs. At the same time European nobles were trying to convince Church leaders that aggressive military activity could be valuable when used against the enemies of Christendom. Then in 1095AD, Pope Urban appealed for volunteers so that the Holy Lands could be liberated. Then after almost twenty years, Pope Paschall II launched a crusade against the Muslims of the Iberian Peninsula by promising that those who participated would receive remission from their sins. The first assault was called the Catalan-Pisan Expedition and it met with mixed results. Then just a few years later Alfonso I of Aragon, and a group of French Crusaders who had fought in the Holy Lands, would fight a seven month siege until they captured the city of Zaragoza.
Then, in 1031AD, the political authority in AL-Andalus collapsed. Muslims living in the peninsula would no longer follow Umayyad caliph. Instead, they broke into a series of states called taifas. At this time they're power base had weakened and they had no central authority. It didn't take long before they no longer had a military. Severely weakened, the Christian peninsula leaders saw their opportunity. They launched a series of attacks against the Muslims in the southern Iberian Peninsula in 1145. A few months later, Alfonso VII would hold Cordoba and two other cities. Lisbon would fall to a contingent of crusaders who were on their way to the Holy Land.
Then in 1211AD, the Muslims in North Africa would launch another attack. With the support of the pope, King Alfonso VIII and a contingent of Christian troops would emerge victoriously at the Battle of Las Navas de Tolosa. Both Cordoba and Valencia would fall in 1236AD and Seville would fall 1248AD. Muslim Spain was soon confined to Granada, where it would survive until 1492AD.