The Reconquista refers to the gradual reclamation of the Iberian Peninsula by the Christians following the Islamic conquest. It began in the 8th century and lasted approximately 700 years. The term is also occasionally used to describe the increasing Mexican population in the southwestern United States.
Beginning in 711, Muslims from North Africa began invading the Iberian Peninsula. By 719, they had conquered almost all of it, but the Christian kingdoms regrouped and fought back. Their progress was slow initially, but the Crusades gave them additional support and they were able to slowly drive the Moors out of the Iberian Peninsula. The last Muslim kingdom to fall was Granada in 1492.