The baths of Trajan were designed, like the emperor’s other public works, by the architect Apollodorus of Damascus. He erected the new complex over the remains of the Domus Aurea, destroyed by fire in 104 AD. The baths were opened five years later.
They covered an area of over 100,000 square metres, almost half of which was occupied by the central building. Trajan’s were the first large baths where the principal building was flanked by an outer court with an exedra, a model imitated in all subsequent large bathing complexes. Some remains of Trajan’s Baths can be found in the park of the Oppian hill.