Barletta Castle was initially erected in the 10th century by the Normans as a typical motte and bailey structure. During the Crusade period, it was a used as a hostel for soldiers leaving for the Holy Land. It was upgraded and enlarged substantially under the reign of Frederick II between 1225 and 1228. This corresponds to the period in which he launched a crusade from here, the Sixth Crusade.
The castle was later expanded under the House of Anjou, when Barletta became an important centre of Aragonese-Spanish control in the area, in 1527. Charles had the building expanded again and the four massive bastions added to create the present fortress form. In 1915 the fortress, then in use as a barracks and military store, was bombarded by the Austro-Hungarian scout cruiser SMS Helgoland. In September 1943 it was the setting of an Italian military defence unit against a German army.
To enter the castle you cross a stone bridge leading to the entrance. Through the doorway, then, you have access to different areas, such as the square courtyard, the ancient seat of the guard and the chapel in which the castle were buried. From the courtyard, you can hop on to various scales, with which you can reach the top floor or the stands.
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.