Oeste Towers (Torres de Oeste) is located at the head of the Ría de Arousa. The towers remaining today are the ruins of Castellum Honesti. In the 9th century, King Alfonso III of Leon built the castle as a defense against Viking attacks. The two remaining towers are from this period, and have a pre-Roman style. Pre-Roman ceramics and bronze tools have been discovered at the site.
Two centuries later, King Alfonso V of Leon donates the fortress to the bishopric of Iria-Compostela, held at that moment by bishop Vestruarius. Subsequent bishops Cresconio, Diego Pelaez and Diego Gelmirez undertook the commitment to strengthen the Castle in order to protect the holy site of Santiago de Compostela. The structure of the Castle was defined in the 12th century. At that time, the enclosure of the Castle was formed by seven towers, and it was surrounded by marshes. The Castle has a 12th-century chapel built by Gelmirez to honor the apostle Saint James. The Castellum Honesti began its decline in the 15th century.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.