With a capcaity of 3000 people,the Terme di Diocleziano is a complex of baths, libraries, concert halls and gardens that was ancient Rome's largest.

The baths were built between the years 298 and 306.

Although many baths in and around Rome had the same elements, the Baths of Diocletian are unique by their size.

Many of the rooms have been preserved because various parts later were converted to ecclesiastical or other use, including: the Basilica of Santa Maria degli Angeli e dei Martiri,
the church of San Bernardo alle Terme
in the main hall, part of the Museo Nazionale Romano
the 'octagonal aula', also now part of the National Roman Museum.