Imperial construction from AD 298 to AD 306
The complex was built between AD 298 and AD 306 and covered about 13 ha (32 acres), making it one of the largest bath installations in ancient Rome. Even in partial form, the surviving scale explains how public bathing also functioned as social and political infrastructure.
Michelangelo's 1561 transformation
In 1561, parts of the baths were adapted into Santa Maria degli Angeli e dei Martiri, with design work commissioned from Michelangelo. That layer is one of the strongest on-site moments because you can read Roman engineering and Renaissance interpretation in the same spatial sequence.
From 1889 museum roots to modern galleries
The National Roman Museum was founded in 1889, and the baths became one of its anchor seats. Since 1998, the site has expanded as an archaeological and exhibition center, which is why your visit now mixes monumental ruins, cloister spaces, and curated displays in one stop.