A city of southwest Spain on the Guadalquivir River north-northeast of Cádiz. An important settlement under the Romans, Vandals, and Visigoths, it was conquered by the Moors in AD 712 and later taken by Ferdinand III of Castile, who made it his royal residence in 1248. The city especially prospered after the discovery of the New World and served as the chief port of colonial trade until the early 1700s.