The siege of Seville (July 1247 – November 1248) was a 16-month successful investment during the Reconquista of Seville by forces of Ferdinand III of Castile. Although perhaps eclipsed in geopolitical importance by the rapid capture of Córdoba in 1236, which sent a shockwave through the Muslim world, the siege of Seville was nonetheless the most complex military operation undertaken by Fernando III. It is also the last major operation of the Early Reconquista. The operation also marked the appearance of indigenous naval forces of Castile-León of military significance. In effect, Ramón de Bonifaz was the first admiral of Castile, although he never held an official title of that kind.In 1246, after the conquest of Jaén, Seville and Granada were the only major cities in the Iberian Peninsula that had not acquiesced to Christian suzerainty.