The castle at Pythio, one of the most important and best preserved examples of military architecture in Greece. It is set on a low mound at the north-eastern edge of the village Pythio, near river Evros, very close to the Turkish borders.
The castle was founded by John Kantakouzenos (later an emperor) around 1330-1340. It served as residense and stronghold during the civil war against the emperor John III Palaiologus. The usage of the castle by the Byzantines did not last long. It was one of the first forts captured by the Turks when they invaded in Europe. Later a village developed around the castle.
The place became known later, in the years of the Greek Revolution, because Patriarch Kyrilos VI who was executed by the the Turks in Adrianople in 1821, was buried here.
The central tower still stands: it was built at the heart of the fortress and dates back to 1331. Another, smaller, tower of the same shape but built at a later date, and the wall between the two towers, have also survived, forming the arched gateway of the main entrance which led to the interior courtyard, with a number of makeshift facilities for the guard or sentry. The larger tower appears to be identical to those in Paleapolis (in Samothrace island) and in Adrianoupolis, as well as those to be found in the area around Constantinople.
The second tower, which was built purely for defense purposes, had three floors and could be reached by stairways and points of access from either the courtyard of the main tower. On the northern boundary of the natural angle of elevation, which was severed by the laying of a railway line and a road, there may well have been a third tower. Part of the exterior fortification of the fortress can be seen in the modern settlement of Pythio today. Besides being a work with a military and defensive purpose, the fort was also built as a splendid monumental facility for the Emperor.
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.