Burgo de Osma, Spain
10th century
Íscar, Spain
13th century
Villaviciosa, Spain
15th century
Merindad de Río Ubierna, Spain
14th century
Urbel del Castillo, Spain
15th century
Alija del Infantado, Spain
15th century
Encinas de Esgueva, Spain
14th century
Valle de Mena, Spain
14th century
Montuenga de Soria, Spain
Middle ages
Narros de Saldueña, Spain
15th century
Condado de Castilnovo, Spain
12th century
Alcuetas, Spain
15th century
Arcos de Jalón, Spain
14th century
Villavellid, Spain
15th century
Cea, Spain
15th century
Mazuelo de Muñó, Spain
14th century
Valle de Valdebezana, Spain
14th century
Hornillos de Cerrato, Spain
15th century
Ciria, Spain
9th century AD
Rivilla de Barajas, Spain
15th 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.