Thermae Neptuni
About
Ostia's most famous bath complex, its floors covered in black-and-white mosaics of Neptune's chariot, tritons and sea nymphs. Hadrian funded the project himself, but construction ran from about 117 to 138 CE and wasn't dedicated until 139, under Antoninus Pius. In 117 this block still held an older Domitianic bathhouse, whose cistern survives beneath the later palaestra.
What happened here
The furnaces are lit before dawn and the water is hot by the eighth hour, which is when the town arrives. The circuit is a habit: undress and hand your clothes to an attendant who may or may not be watching them, exercise in the courtyard, sweat in the hot room, scrape the oil and dirt off with a curved bronze strigil, then the warm pool and the cold plunge. Entry costs a coin small enough that almost nobody is priced out, and on a benefactor's birthday it is free. There is food, drink, ball games, gambling, hair-plucking, business and shouting; a writer complaining about the noise from the flat above is complaining about all of it. Men and women bathe at different hours, or in separate wings.
Sources
Roman Maps shows the empire frozen at 11 August 117 CE, the day Trajan died — its moment of greatest territorial extent. Explore the full map →