The Roman imperial bath complexes (thermae) were one of the most spectacular architectural projects, in which the architects synthesized the tradition of Greek baths and new technologies. The imperial baths of Trajan and Caracalla were the most famous. These monumental buildings were decorated with sculptures, columns, and mosaics. But the Roman baths were not only a center of architectural innovation, but also a place of intense cultural life. The Romans relaxed from the everyday stress in the baths, and also communicated with each other about the social issues. In the baths, the politics often resolved key diplomatic issues, and thus there were many scheming and gossip. In fact, such monumental imperial buildings represented the Roman society both symbolically and physically as well as reflected its historical transformation during different periods. Accordingly, the architecture of imperial baths reflected the social structure of the ancient Rome, dividing its elements according to their economic status, gender, and political authority that were also reflected in the ritual of bathing.
In the early stages of the Roman Empire, the bathing primarily was in private homes, and the ritual of bathing acquired to the status of collective action. In fact, the Romans took a bath mainly for health and cleanliness, not for fun. According to Seneca, they washed their hands and faces every day, and took a bath once a week . The prolonged relaxation in the warm atmosphere has always created a certain mood, because the imperial baths was like the entertainment center during the period of the Roman Empire. The visitors did not only have a bath, but also swam in pools, enjoyed food and drink, listened to the music, and even danced . In other words, the Roman imperial baths were the prototype of modern entertainment centers with different types of pleasure. Moreover, the imperial baths often had libraries, because the ritual of bathing was similar to the practices of holiday . The Roman baths quickly became the public clubs, where most of the Romans spent their free time. For instance, the Trier Imperial Baths was the most famous complex, and it was designed as a part of the Roman monumental architecture.
The architecture of the Roman imperial baths reflected the economic status of the Romans, so the baths were divided into rich and poor people. In this case, everyone could attend the baths, and thus there were many rooms according to the social statuses. The rooms for rich citizens were well decorated. The rich citizens could come to the baths with their servants who helped them to do some procedures. Accordingly, the construction of terms required the complex architectural decisions, which were distinguished them from the Greek baths. In addition, the government carefully monitored the cleanliness of baths, and thus they often did serious repairs of the complexes. Obviously, the rich sectors were repaired more than others, including their cultivated mosaics and decorations. However, much sculptural ornamentation had a high aesthetic level, and performed only a decorative role. Further, the rich and noble citizens believed that it was necessary to upgrade or build new terms for the poor Romans, because it would greatly increase their popularity among the people.
The construction of these grand buildings was possible because of the extensive experience that was gained by the Roman architects in the creation of concrete vaults and domes. In these Roman buildings, the structural shapes formed a complex spatial structure, interacting with each other. The Roman architects developed an efficient central heating system with heated floors and walls, which was called hypocaust (hypocaustum) . In the baths, water and air were heated thanks to the oven (praefurnium), which were then circulated under the floor and wall cavities. It used the double coverage in order to keep warm in the floor. The highest coating consisted of the large bricks, clay, and the basic coating. All this structure was kept on the small brick pillars (pilae), which immediately placed in a checkerboard pattern . The rectangular bricks were built in the walls, and the hollow bricks (tubuli) were inside of the building, which were supported by the metal staples. In general, these architectural innovations virtuously reflected the power of Rome.
The Rome Empire deliberately constructed these monumental structures in order to demonstrate its political authority among other countries. Moreover, the sense of geopolitics was that the Romans have transferred their key political ambitions into the monumental architectural projects, and thus the imperial baths were large and massive. One of the main halls was usually designed by circularity, which was covered with a dome. The floors of central hall were represented by the three cross vaults (25 m), which relied on the cross foundations . Moreover, the cylindrical vaults were constructed between them. The enfilades of large and small halls had complex interior, luxurious finish, and thus often impressed visitors. The visual effect of lightness was achieved due to the warrant elements and vaults . The further development of compositions such rotunda was possible due to the widespread use of dome coverings in the Roman baths.
There was also the division by gender as well as the architecture reflected the attitudes to men and women in the Roman society. For example, the Pompeii baths were divided into two parts, one of which was intended for women . From the time of Hadrian, women had a special time for their bathing. Some have suggested that there were separate rooms for women, where they solved their social problems. In fact, women never took a bath with men, because their status has always been lower. In addition, it prevented of transformation of the bath into a brothel.
The ritual of bathing was also important, and it had both recreational and social roles. The Roman imperial baths begun from a term locker. In this cool room (apoditerium), the Roman visitors left their clothes . Following the washing rules, then they went to the room (tepidarium) where the temperature was heated about 40 degrees. For the Romans, it was important to warm up gradually. The presence of the pool allows to relax and to improve their condition. Another room, which was necessary to visit, was called kallidarium . This room also expected the availability of basin with warm water from the hot springs. For those who loved very hot temperatures, there was a separate room – lakonium. After the intense warming, the Romans had an opportunity to rest and enjoy in the cool pools. Most of the Romans could not pass lavarium, where they rubbed their bodies by the fragrant oils .
Thus, the Roman imperial bathes became the center of social and recreational activities, where the crucial political issues have been resolved. Therefore, the main thing in the rituals was that the previous private activity has transformed into the collective social activity. Hence, the architecture of baths mirrored the social structure of Rome. The baths were simple on the surface, but inside every sector reflected a social level. The most impressive were sectors for rich Romans that were decorated with mosaics and paintings. The baths also contained little sections for women, indicating a change in the social status of women at the time. However, the main thing was that the imperial baths reflected the high economic level of Rome, since the construction of massive structures required significant resources. Therefore, the baths were a kind of demonstration their political power among other countries, thus confirming its status as the most powerful empire in the ancient world.