The Church of Agioi Theodoroi is one of the oldest and largest chapel in Mystras. It is located in Kato Hora, the lowest part of Mystras Old Town. The church was constructed between 1290-1295 by the monks Daniel and Pahomios. Originally, it was the katholikon of a monastery and then it became a cemetery church.
The architecture of the church is different than the usual Byzantine architecture and ressembles to the Monastery of Osios Loukas in Distomo Boetia, but in a more developed form. The architecture gradually points to the top and the dome is pretty impressive. The interior of the church distinguishes for the impressive frescoes that date from the 13th century, such as the portraits of the Emperor Manuel Paleologos. In this church, there is also the tomb of the Despot of Peloponnese Theodore I.
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.