The Reconquista was a long campaign during which the Christians to the north of the Iberian Peninsula gradually reclaimed the territory they had lost to the Moors in the 8th century. The Moors began their conquest of Iberian in 711 and by the turn of the century, had most of the Iberian Peninsula under their control.
However, they couldn’t take the territories to the northwest of Iberia and their advance was checked in the northeast by the Franks. In time, the Christian populations in northern Iberia bordering Moorish territories formed independent principalities of their own which evolved into kingdoms over time.
These kingdoms would then slowly advanced southwards, retaking the Moorish territories and making them a part of Christendom.
Although the “Reconquista” was not a concerted campaign launched by collective Christian forces, the term has been historically used to denote the overall campaign meant to retake the Moorish territories. The first recorded instance of successful resistance to Moorish conquest of Iberia was the Asturian rebellion led by Pelagius.
Pelagius rebelled against the Moorish control of the northern region of Asturias. The Moors sent a sizable army to suppress the rebellion but Pelagius was able to rout this army with the help of a handful of followers in the 722 Battle of Covadonga. This battle is historically regarded as the beginning of the Reconquista and led to the establishment of the independent Kingdom of Asturias in northern Iberia.
This was soon followed by the 732 Battle of Poitiers in which the Frankish military commander, Charles Martel, decisively defeated a large Moorish army in northeast Iberia. This victory definitely halted the advance of Moorish forces into Frankish territories and marked the maximum extent of Moorish Iberia.
Throughout the Reconquista period which lasted from early 8th century to late 15th century, the Christian kingdoms in northern Iberia were the frontline entities in the Reconquista effort. Many of these kingdoms were originally independent principalities which later grew into kingdoms. Over time, these kingdoms would splinter, merge and re-merge with each other.
The most notable of these were the kingdoms of Castile, Aragorn, Navarre, Leon, Asturias and Portugal. As the Moorish authority in regions bordering these kingdoms diminished, these kingdoms slowly advanced southwards, sometimes at the expense of each other.
By the 11th century, Cordoba Caliphate had collapsed and a civil warfare raged in Moorish Iberia. Christian kingdoms to the North took advantage of the situation and were able to reclaim a sizable portion of the northern Moorish territories. The stability of the Moorish territories declined steadily in the subsequent centuries so that Christian kingdoms steadily advanced southwards.
By the 13th century, the Emirate of Granada in southern Iberia was the only Moorish territory in the region. The Christian kingdoms repopulated the regions they regained with Christian populations, effectively countering the demographic effects of the centuries-long Moorish rule.
In 1492, the Catholic monarchs of Spain were able to effectively subdue the last stronghold of Moors in Granada. The fall of Granada marked the effectively end of Moorish rule and the completion of Reconquista which resulted in the reclaiming of the entire Iberian region from the hands of the Moors.