The Monastery of the Cross was built in the eleventh century, during the reign of King Bagrat IV by the Georgian Giorgi-Prokhore of Shavsheti. It is believed that the site was originally consecrated in the fourth century under the instruction of the Roman emperor Constantine the Great, who later gave the site to king Mirian III of Kartli after the conversion of his kingdom to Christianity in 327 AD.
Legend has it that the monastery was erected on the burial spot of Adam's head—though two other locations in Jerusalem also claim this honor—from which grew the tree that gave its wood to the cross on which Christ was crucified.
Due to heavy debt the monastery was sold by the Georgians to the Greeks in 1685. It is currently occupied by monks of the Greek Orthodox Patriarchate of Jerusalem.
The remains of the crusader-period monastery forms a small part of the current complex, most of which has undergone restoration and rebuilding. The crusader section houses a church, including a grotto where a window into the ground below allows viewing of the spot where the tree from which the cross was (reputedly) fashioned grew. Remains from the 4th century are sparse, the most important of which is a fragment of a mosaic. The main complex houses living quarters as well as a museum and gift shop. The monastery library houses many Georgian manuscripts.
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.