At the beginning of the fourth century Roman Emperor Constantine I the Great had residence in Arles and was named the city the second capital of his Empire. Constantine I went down in history as the ruler who made Christianity the main state religion-and post-capital of the Roman Empire to Constantinople (then Byzantium). In Christianity Constantine is revered as a Saint equal to the apostles king.

During this period in Arles were built Thermae public baths, which today is considered one of the best preserved Roman baths in France. Roman baths were built in the likeness of the Greek, was richly decorated with mosaics, sculptures, columns and other decorations. In France also preserved baths of Cluny on the banks of the Seine, located in the Latin quarter of Paris.

Baths in Arles were built on the banks of the Rhone, not far from the amphitheatre. The remains of the baths were discovered in the XVI century, during the examination of the local historians of the buildings along the riverfront. By mistake ruins of the baths took for the remains of the Imperial Palace and for several centuries were called "Palais de La Trui". In the nineteenth century, when the ruins partially cleared, it was found the true purpose of this building. Now the southern part of the Thermae is underground, and the North was cleared in the last century. Then over former ovens was erected a canopy, and the remains of the baths were open to visits by tourists.

Among the ruins of the baths can be seen the remains of several rooms: the caldarium (hot baths), the tepidarium (room with warm baths), laconium (hall with dry steam), as well as hypocaust double - layer floor, under which was heated furnaces air under the floor columns were built of brick tiles. The tepidarium was located in a preserved semicircular apse with three Windows, and the frigidarium (cold water pool) is not preserved.