The bricks and stones of the Theodosian Walls extend over six kilometers along the coast of the Sea of Marmara to the northern shore of the Golden Horn. It is the glorious work of Emperor Theodosius II, built at the beginning of the 5th century under the supervision of the city prefect Anthemios, and still shapes the cityscape today. Originally, the wall had a total of eleven gates and included 192 towers in its complex.
Scientists classify it as one of the most architecturally successful fortifications in the history of war technology. This conclusion is not only based on the fact that the wall served as a protective wall for the city for more than 1,000 years and protected it from the enemy, but also because many of the most drastic events in the city’s history are closely related to this extraordinary structure. One of the main reasons for initiating the large-scale project was the rapid expansion of Constantinople, which meant that many urban areas were completely unprotected. Secondly, because of the dangers of the migration, which resulted in a massive threat; at that time especially from Goths and Huns. Gradually, the Theodosian Walls developed as protection against attacks from the land as well as from the sea side. Due to earthquakes and the resulting fires, the construction was rebuilt and improved over and over again. This resulted in a triple rampart system and an intrusion through the bulwark was almost impossible.
However, at the beginning of the 13th century, the Fourth Crusade took place, in which Crusaders were able to enter the city by chance via suboptimal fortified sea walls. The following almost complete plunder of the city became fatal to Constantinople. The Byzantine Empire never recovered from this disaster.
However, the city wall was completely stormed for the first time by the Ottomans when in 1453, after a seven-week siege of the city, the field army of Sultan Mehmed II was far superior. The siege technique of the Ottomans led to a major turning point in the history of warfare. To storm the city in an unexpected way, the entire Ottoman fleet was moved from the Sea of Marmara to the top of the Golden Horn over land, along with other major assaults and the construction of a pontoon bridge. This meant the end of Constantinople, at that time largely depopulated and already impoverished, and thus the entire Byzantine Empire.