Thermae thieves and pickpockets were known to frequent the baths. The changing room was known as the "apodyterium" (from Greek "apodyterion" from "apoduein" "to take off"). In many ways, baths were the ancient Roman equivalent of community centres. Because the bathing process took so long, conversation was necessary. Many Romans would use the baths as a place to invite their friends to dinner parties, and many politicians would go to the baths to convince fellow Romans to join their causes. The thermae had many attributes in addition to the baths. There were libraries, rooms for poetry readings, and places to buy
Ancient Roman architecture air. The Roman architect Vitruvius, writing about the end of the 1st century B.C., attributes their invention to Sergius Orata. Many remains of Roman hypocausts have survived throughout Europe, western Asia, and northern Africa. The hypocaust was an invention which improved the hygiene and living conditions of citizens, and was a forerunner of modern central heating. Hypocausts were used for heating hot baths (thermae), houses and other buildings, whether public or private. The floor was raised above the ground by pillars, called pilae stacks, with a layer of tiles, then a layer of concrete, then another of tiles on top;