Chiprovtsi, Bulgaria
10th century AD
Montana, Bulgaria
1850-1853
Pliska, Bulgaria
875 AD
Sofia, Bulgaria
13th century
Razgrad, Bulgaria
1533
Veliko Tarnovo, Bulgaria
17th century
Veliko Tarnovo, Bulgaria
1846
Vidin, Bulgaria
14th century
Strupets, Bulgaria
14th century
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.