Commissioned by Emperor Domitian starting from around 96 AD,[2] the complex of baths occupied space on the southern side of the Oppian Hill on the outskirts of what was then the main developed area of the city, although still inside the boundary of the Servian Wall.

[3] Early Christian writers were thought to have misnamed the remains the "Baths of Domitian"[4] but this was shown to be a correct attribution for the emperor who began the project, even if Trajan completed the work.

[5] The baths were utilized mainly as a recreational and social center by Roman citizens, both men and women, as late as the early 5th century.

[7] The baths were thus no longer in use at the time of the siege of Rome by the Ostrogoths in 537; with the destruction of the Roman aqueducts, all thermae were abandoned, as was the whole of the now-waterless Mons Oppius.

The main chambers were arranged in a sequence along a central axis from northeast to southwest (natatio–frigidarium–tepidarium–caldarium), and were flanked on either side by a network of rooms and open courts which were strictly symmetrical with one another.

[17][12] Several fragments of the Forma Urbis depict the plan of the Baths, one of which preserves three letters ("AIA") from the inscription identifying the complex as the "THERMAE TRAIANI".

[18] The Baths were slowly dismantled over the centuries, as the marble and brick were sold by the monks of San Pietro in Vincoli to stonemasons for re-use and burning into lime for mortar.

[19] Large parts still remained standing at the beginning of the sixteenth century, when architects like Andrea Palladio studied the ruins and were able to reconstruct the floorplan.

[20][21] The archaeological excavations of 1997 also led to the discovery of a large (about 10 m2) frescoed bird's-eye view of a walled port city, a unique survivor of such a subject, in a buried gallery or cryptoporticus beneath the baths, which pre-dated their construction, but postdated Nero's Domus Aurea.

[22] Additionally, the discovery of a 16 m mosaic was announced in July 2011 in what is believed to be a Musaeum, a place dedicated to the goddesses who inspire the creation of the arts, featuring a nymphaeum (fountain room), which was buried to build the baths above.