The Baths of Trajan were a massive thermae, a bathing and leisure complex, built in ancient Rome starting from 104 AD and dedicated during the Kalends of July in 109. Commissioned by Emperor Trajan, the complex of baths occupied space on the southern side of the Oppian Hill on the outskirts of what was then the main developed area of the city, although still inside the boundary of the Servian Wall. The baths were being utilized mainly as a recreational and social center by Roman citizens, both men and women, as late as the early 5th century.
The complex seems to have been deserted soon afterwards as a cemetery dated to the 5th century (which remained in use until the 7th century) has been found in front of the northeastern exedra. The baths were thus no longer in use at the time of the siege of Rome by the Goths in 537; with the destruction of the Roman aqueducts, all thermae were abandoned, as was the whole of the now-waterless Mons Oppius.
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.