In 711 an army of Arabs and Berbers from North Africa, united by their faith in Islam, crossed the Strait of Gibraltar and arrived on the Iberian Peninsula. In less than a decade the Muslims brought most of the peninsula under their domination; they called the Iberian lands they controlled al-Andalus. Although the borders of al-Andalus shifted over the centuries, the Muslims remained a powerful force on the peninsula for almost eight hundred years, until 1492, when they were expelled by Ferdinand and Isabella. …