Gaztelu Zahar

Gaztelu Zahar gaztelua is located in Irún, a municipality in modern Spain, and was built by the kingdom of Castile in the early 16th century. Its construction was commissioned by King Ferdinand II of Aragon in 1518 to secure the frontier between Castile and neighboring regions, specifically to guard against incursions from France and the Kingdom of Navarre.

The castle’s strategic location on a hill overlooking the Behobia pass allowed it to control this key border crossing, which was critical during the conflicts of the early 1500s. Following the Franco-Navarrese invasion of Gipuzkoa in 1512, the site was selected to prevent French forces from crossing the nearby Bidasoa River. After completion, Hernán Pérez de Yarza was entrusted with the castle’s command, highlighting its military importance.

During the turbulent period of 1521-1522, which included the Battle of San Marcial, the castle saw conflict and was briefly occupied by opposing forces. As a result, it sustained significant damage. To prevent its use by Navarrese troops seeking to reclaim their kingdom, Emperor Charles I ordered the castle’s demolition in 1539. This process, finished by 1542, led to most of the castle’s stone materials being repurposed in the defensive walls of the nearby town of Fuenterrabía, now Hondarribia.

In later centuries, the castle became known as Gaztelu Zahar, or “old castle,” a name reflecting its ruined state after demolition. There were several suggestions for its reconstruction in the 1600s, and in 1719, some restoration and fortification activities took place connected to the War of Succession. More recently, the Basque Government recognized the site’s archaeological value in 1997, granting it preliminary protection. Its historical importance was further acknowledged in 2010 when it was added to the Monument Ensemble list associated with the Basque section of the Way of St. James pilgrimage route.