Mezquita-Catedral de Córdoba -

"According to a traditional account, when the exiled Umayyad prince Abd al-Rahman I escaped to Iberia and defeated the governor of al-Andalus, Yusuf ibn Abd al-Rahman al-Fihri, he found the Cordovese divided into various sects, including the Gnostics, Priscillianists, Donatists, and Luciferians. His ambition was to erect a temple which would rival in magnificence those of Baghdad, Jerusalem, and Damascus, and approach in sanctity the fame of Mecca. Above a Christian church dedicated to Saint Vincent, Abd al-Rahman decided to raise his great mosque. He offered to buy the church and the plot. The negotiations for the sale were placed in the hands of the Sultan's favourite secretary, Umeya ibn Yezid. Under the terms of the transfer, the Cordovese were permitted to reconstruct the church formerly dedicated to Saints Faustus, Januarius, and Marcellus, three Christian martyrs whom they deeply revered." (en.wikipedia.org/wiki/Mosque-Cathedral_of_Córdoba)