The Aranibar Palace is currently the oldest surviving merchant's house in El Puerto de Santa María. Its owner, Juan de Aranibar y Alberro , a native of San Sebastián and descendant of a family of Navarrese origin, came to El Puerto as a soldier and Master of the Horse to the Duke of Medinaceli. Considered the most powerful and wealthy man in the city, in the mid-17th century he held the position of councilman and founded the Hospital de Mujeres del Amparo y San Sebastián (Women's Hospital of Protection and Saint Sebastian). Related to the Vizarrón family, his presence in El Puerto was the origin of one of the most important merchant families in the region: the Vizarrón Aranibar family .