An important part of Roman civilization were the “thermal baths”. No Roman city within the empire could do without a public bath. The often huge constructions usually had many rooms and buildings, all serving different purposes: Swimming pools, saunas with different temperatures and humidity as well as sports facilities and recreation rooms.
Milestone of civilization
The ancient Greeks already had public baths, but they tended to only build a few pools, in which one could only stand waist-deep in the water to wash themselves. The Romans continued the development of these constructions and extended their purpose to exceed that of simple bodily hygiene.
In all of the empire’s cities baths were an indispensable part of Roman culture. Even smaller cities afforded the construction of public thermal baths, usually in close proximity to the forum. Even the Roman army built baths in many garrisons for its Legionnaires.
“The thermal baths of Caracalla in Rome”
Normally Rome’s thermal baths opened around midday and remained open for all citizens, rich and poor, until the evening hours. Under the rule of Diocletian for example, the entry fee for the Roman baths was two dinars, the smallest of the Roman’s currency units. On major public holidays a visit could also be free of charge.
They also were important hygienic institutions, because a constant flow of water was only available in the mansions of rich, important people. The common Romans had to get their water from open wells, which were fed by large conduit systems.
Typical elements of a Roman bath
Typical components of a Roman bath include:
• apodyterium – changing rooms
• palaestrae – training rooms
• natatio – an outdoor swimming pool
• laconica and sudatoria – very hot, dry and humid saunas
• calidarium – heated thermal room with a warm water swimming pool
• tepidarium – warm room, indirectly heated and with a lukewarm swimming pool
• frigidarium – cool room, unheated and with a cold water swimming pool. This room was often very big and had a domed roof. It was the heart of the baths.
• Rooms for massages and other treatments.
Additionally thermal baths could also include cold water diving pools, private bathrooms, toilets, libraries, conference halls, water features and gardens.
“Layout of Diocletian’s thermal baths in Rome: 1 = caldarium 2 = tepidarium 3 = frigidarium 4 = natatio 5 = palaestra 6 = entrance 7 = apodyterium”
The thermal baths also played a key role in Roman architecture. The oldest, preserved domed building of Roman architecture is the frigidarium of the Stabianic thermal baths in Pompeii from the 2nd century BC.
Thermal baths were built out of millions of fireproof terracotta bricks and richly decorated with marble walls, statues, mosaics and frescoes. Tunnel vaults and iron supports advanced the construction techniques. The invention of cement enabled load-bearing walls to be placed farther and farther apart. These techniques were used in other public buildings, too, and later also in the construction of churches.
“Interior view of the Caracalla thermal baths”
The first thermal baths don’t seem to have been planned properly, as they often appeared to be an unordered collection of different rooms. But by the end of the 1st century AD, the Romans has developed harmonious, symmetric buildings, which were often surrounded by gardens and parks. Older constructions were usually heated with smudge pots, but by the 1st century BC sophisticated heating systems had been developed. Underfloor heating systems, called hypocaust, were powered by wood burners.
The idea itself wasn’t new. The Greeks already knew the concept, but the Romans adopted and refined this idea like so many others. Large burners sent warm air below the floor tiles, which were placed on small pillars, hollow cylinders or round bricks.
“Floor construction of a thermal bath“
The walls, too, were converted to heating apparatus, as rectangular tubes were placed within them and then connected to the burners. Special bricks with insulating structures reduced the loss of heat to the outside. The introduction of glass windows in the 1st century enabled the temperature within the buildings to be better regulated and even the use of the sun’s rays as another source of heat.
The immense amount of water that was required for the big thermal baths was delivered via aqueducts and stored in large tanks on-site. The reservoir of Diocletian’s thermal baths in Rome for example contained 20,000 cubic meters of water. The water was heated in large lead boilers and could be piped through lead pipes in order to regulate the warm water pools’ temperatures.
“Domed structure of the Caracalla thermal baths”
Famous thermal baths
Among the most famous and sophisticated thermal baths we still know of today are the baths of Leptis Magna (completed in 127 AD) with their well-preserved domes, the baths of Diocletian in Rome, the large site of Timgad near Ephesos and the baths in the English city of Bath from the 2nd century. In Germany, too, there is manifold historical evidence of the Roman bathing culture, for example in Trier (Augusta Treverorum) and Cologne (Colonia Claudia Ara Agrippinensium).
“Remains of the Roman imperial thermal baths in Trier“
The Caracalla baths in the south of Rome are among the most well-preserved and were, besides the baths of Traianus, the second largest in the empire’s capital. They were completed in 235 AD and the huge walls and arches still testify to the immense size of the structure. 6.9 million bricks were used, 252 pillars hold up the construction on the inside. Over an area of 337 x 328 meters the construction rose up to 30 meters in height and included a one-meter-deep Olympic swimming pool.
An unusual round caladarium with a dome of a diameter of about 36 meters was also part of the construction. It was fitted with glass windows to use the sun’s heat. Furthermore there were two libraries, a water mill and even an artificial waterfall.
The building had four entrances and offered room for up to 8,000 visitors a day. 6,300 square meters of marble and granite decorated the walls and the ceiling was ornate with glass mosaics, which reflected the light from the pools, thereby creating iridescent light effects. Two six-meter-high fountains and a gallery leading to a promenade terrace were also included.
The baths were heated by 50 boilers, burning 10 tons of wood every day. Besides the impressive side walls, one can still find many rooms with the original marble cladding and mosaics, which for example show fish scales and scenes with mystical ocean creatures.
With the downfall of the Roman Empire, this European achievement also faded into obscurity. The bathing culture of the Middle Ages with its wooden tubs was barely a shadow of the ingenuity of Roman thermal baths.