The history of Nymphaeum, or the main public spring of Philadelphia, as Amman was called in the Hellenistic and Roman eras, dates back to the end of the second century AD, only a short walk from the Roman Theater and the Odeon. Built over caves with running water, believed to be sacred to the mythical nymphs, the nymphaeum were public gathering areas and were seen as a sign of the city's wealth.