The mediaeval fortifications of Hondarribia (Fuenterrabia) were enlarged as the population grew and the town's strategic importance increased. The Catholic Monarchs undertook significant improvement and enlargement, although these constructions had to be repaired at several points due to the ravages of war. Charles V once again renovated the fortifications and in the second half of the sixteenth century engineers El Fratín and Tiburcio Spanocchi carried out additional work.
Hondarribia was surrounded by a modern, roughly pentagonal, fortification, dominated to the west by hills and surrounded on all other sides by the sea. Clockwise, the bastions were: St. Philip's (of which some remains can still be seen), The Queen's and Leiva, the Mary Magdalene Turret (no remains now visible), the Old Ammunition Tower (no remains), St. James' Bastion (semi-ruined) and the small Bamba Tower (demolished in 1729).