A failed Viking siege of this city in 844 ended with 400 Vikings being hanged on palm trees by this city’s defenders, who then constructed its first shipyard. A qadi from this city named Abu al-Qasim founded the Abbadid dynasty, which ruled an independent kingdom based in this city. Ferdinand the Great of Castile forced this city’s rulers to hand over the remains (-5[1])of a saint from this city who authored an encyclopedia (15[1])called the (*) Etymologie. The Almohads constructed the Torre del Oro and a minaret that would later become the Giralda (“hee-RAL-dah”) belltower in this city, which was the home of a scholar named Isidore. Ferdinand and Isabella baptized their son in this city’s cathedral, which is adjacent to a palace called the Alcázar. For 10 points, name this Spanish city on the Guadalquivir (10[1])River that is the largest city in Andalusia. ■END■