In imperial Rome the public baths ceased to be exclusively used for physical hygiene and sports and increasingly became a place of social intercourse.This necessitated the extension of the existing facilities and the construction of new baths. Emperor Caracalla met this demand when he opened a huge complex in A.D. 217, covering a square site of 11 hectares that could fit about sixteen hundred people in the bath house alone.
On walking through the ruins, which are well preserved, one can still gain a vivid impression of the layout and the huge dimension of the halls.The monumental bath house lay in the central part and had the traditional ground plan with the main rooms on the central axis, the changing rooms, smaller rooms for massage and medical examinations, and the sports areas (palestrae).
The sequence of rooms was impressive, not only for the wide variety of ground plans and types of vaulting but also for the luxury of the fittings.Where today we see only simple brickworks where once pilasters and niches, while the walls were covered with mosaics, frescoes and marble. The architecture and painting were enriched with many fine sculptures, of which only the Farnese Hercules in Naples need be mentioned.The main technical facilities for the baths were in the cellars, which formed a regular network of subterranean streets.
The water of the baths was collected in the huge cisterns that could hold 8.000 m3 of waters; they were concealed behind the flat exedrae of the south-west side of the enclosing wall. Those who had finished bathing could find plenty to do outside the actual bath complex.
They could stroll in gardens that surrounded the central section, or wander through the colonnades of the enclosing walls, which also contained concert and lectures rooms, libraries, shops, offices, inns, and even a subterranean shrine to Mithras.So the bath were in fact a gigantic leisure complex providing for what the roman poet Juvenal called “mens sana in corpore sano” (a healthy mind in a healthy body), with a comprehensive supply of sports and cultural facilities.
The bath could be used until sundown and were free of charge. Only starting in the year 537, when the Goths cut off the supply of water, did the baths began to decay. Then, in 847, an earthquake brought down some parts of the building. But the baths suffered the worst damage through the pontificate of Pope Paul III Farnese (1534-1549), who released them as a quarry for the rebuiling of St Peter's.
It was in this way that many of the sculptures came into the possession of the papal family. The basins of the two fountains before the Palazzo Farnese, for example, also came from the Baths of Caracalla.Most recently the Baths are used as a unique scenario for the summer season of the Opera House of Rome.