Toledo was walled by Romans, and a lot of its stones were reused later in built walls, as the original perimeter was subsequently tripled. The Visigothic King Wamba renewed the Roman fortifications, sculpting in its gates an inscriptions. The inscriptions were destroyed by the Muslims, and restored in 1575 by the Corregidor Juan Gutiérrez Tello.
The Arabs widened the city and the walls. After the Reconquista, the walls were again advanced in outer line and new gates were constructed. The gates and towers of the Walls of Toledo have survived until these days.
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.