The Forum Baths are a ruin of a Roman bath complex in Augusta Treverorum, modern-day Trier. The site was converted in the 4th century CE from some older buildings, dated to around the 2nd century CE. The structure encompassed 8364 m2 The bath house utilized the passive heating of the sun, like many Roman baths, and oriented the caldarium and tepidarium to the south, and the frigidarium to the north.
Along with the other bathhouses, the Forum Baths remained in use through the end of the fourth century. But the complex fell out of use during the early fifth century as Trier was repeatedly sacked during the Migration Period.
In the 13th century, the remains of the bath began being used as a quarry for local buildings. In the 17th and 18th centuries, the Capuchin Order built some of the buildings for their monastery over the eastern part of the bathhouse. In 1802, the monastery was dissolved and nine years later, in 1811, the garden was transformed into a cattle market (German: Viehmarkt), from which the ruins get their name.
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.