The modern tradition retains almost unanimously the name of Antoninian baths, in reference to the emperor Antoninus the Pious (138-161) who would have contributed to their implementation. The inauguration of the complex dates from the year 157 (or 159) and its completion took place in 162 with the construction of the porticoes and other external buildings. Various materials were used for the construction: shell sandstone, Keddhel (travertine stone) from Hammam-lif, hard limestone from Jebel Jeloud, red and grey granite from Italy, white marble from Pentelica and Proconese, cipolin marble from Euboea, yellow marble from Chemtou, pumice, and lava from Sicily and alabaster from Jebel Oust.
Built by the sea, the thermal baths are the largest in Africa (17,850 sq.m. and 19,711 sq.m. if one takes into account the rooms open to the public but located on the lower level and mainly earmarked for services), far ahead of Hadrian's thermal baths at Lepcis Magna, which extend over 6,000 sq.m. The proximity of the sea prevented the construction of service buildings in the basement. These, the only ones still visible on the site, occupied the ground floor and were immediately accessible from the sea through which the enormous quantity of fuel necessary for the operation of the boiler rooms came.
The elongated plan is dictated by the small amount of land available. Accessible through four doors, and designed to function all year round, except for certain spaces, such as the natation (swimming pool), which had seasonal uses, the baths had a symmetrical plan with double rooms. Each bather could use six rooms according to a symmetrical route.
Originally mixed gender, but as scandals increased, the emperor Hadrian (117-138) decided to separate genders and to dedicate the baths to women in the morning and to men in the afternoon. Bathers could bathe for a very modest fee, but sometimes access was entirely free.
The monument operatednormally until the end of the 4thcentury, between 388 and 392 AD, when the great vaults of the frigidarium collapsed. The bath complex was not abandoned and the parts that were still operating continued to be used. The collapse of the vault of the large caldarium in the 5thcentury led to the beginning of the baths demise and the installation of a ceramic workshop on the ground floor. The turning point occurred probably when the last Vandal king destroyed the Carthage aqueduct, thus depriving the monument of the water required for its proper operation.
The exact date of the baths desertion is unknown, but it seems that as early as the middle of the 7thcentury, quarrymen were installed in the basement. Entire columns were taken away to be reused in the mosques of Kairouan and Tunis... The marble and granite were loaded onto boats and sometimes exported far away, to Turkey or Italy in particular. The cathedral of Pisa is said to have been partially built with Carthaginian materials.