 In July 1477, Isabella arrived in Seville, the most populous city of Castile, with the objective of asserting her power over the nobility of Andalusia.In April 1476, Isabella and Ferdinand gave their first exculpation to the Marquis of Cadiz.He had been regaining power while his rival, the Duke of Medina Sidonia, initially the main Isabella supporter in Andalusia, had been falling into dishonour.