This small town was founded in 908 by Sancho Abarca of Navarre to defend the frontier, when it was known as La Guarda. It was originally laid out in the shape of
a ship, with the bow facing North. and the stern South. In 1164 it achieved town status under Sancho el Sabio. In 1194 its fortifications were extended by King Sancho el Fuerte.
From 1367-1461 it was taken many times by the Kings of Castile. In 1461 it finally fell to the Crown of Castile hrough Ferdinand and Isabella.