a victory should be won by a Berber freedman. Accompanied by his son Abd al-Aziz ibn Musa, Musa landed in Spain in 712 with his own army of 18,000 veteran Arabs and proceeded to the further conquest of Visigothic territory. They took Medina-Sidonia and Carmona; then Prince Abd al-Aziz took Hispalis in 712 after a long siege. Until his assassination at the hands of his cousins in 716, the city served as the capital of al-Andalus, the name given the Iberian Peninsula as a province of the Islamic empire of the Umayyad Caliphate. Following the siege and conquest of the city, its Roman name, Hispalis, was changed to the Arabic Išbīliya (إشبيلية) or Ishbiliya. During this period of Muslim rule a richly complex culture developed. The emirate favored the expansion of Islam through concessions to those Christians who converted to Islam, called Muwallads, privileges not enjoyed by those who remained Christian, known as (Mozarabs). The city was called by the name Ixbilia in the Mozarabic language, which became Sivilia, and finally reached the form "Sevilla", as it is known today. The Umayyad dynasty was established in al-Andalus when Abd al-Rahman I took Išbīliya without violence in March 756, then won Córdoba in the Battle of Musarah where he defeated Yusuf al-Fihri, the governor of al-Andalus, who had ruled independently since the collapse of the Umayyad Caliphate in 750. After his victory Abd al-Rahman I proclaimed himself the Emir of al-Andalus, which later became part of the Caliphate of Córdoba when Abd ar-Rahman III proclaimed himself Caliph in 929, and Išbīliya was made the capital of a kūra (territory). Abd al-Rahman I appointed his Umayyad kinsman Abd al-Malik ibn Umar ibn Marwan governor of Seville. By 774 Abd al-Malik definitively crushed opposition to the Umayyads by the Arab garrisons and local elites of Seville and its territory. His family settled in the town and became a major component of the government in Cordoba, serving as viziers and generals of the successive emirs and caliphs, and some of his descendants attempted to wrest the caliphate from the descendants of Abd al-Rahman I. The Ad-Abbas Mosque was built in 830, it currently holds the Church of El Salvador. On 1 October 844, when most of the Iberian peninsula was controlled by the Emirate of Córdoba, a flotilla of about 80 Viking ships, after attacking Asturias, Galicia and Lisbon, ascended the Guadalquivir to Išbīliya,