Paestum has the best preserved Greek temples in the entire world. Founded around the end of the 7th century BCE by colonists from the Greek city of Sybaris, and originally known as Poseidonia. It later became the Roman city of Paestum in 273 BCE. The city continued to prosper during the Roman imperial period, but started to go into decline between the 4th and 7th centuries. It was abandoned during the Middle Ages and its ruins only came to notice again in the 18th century, following the rediscovery of the Roman cities of Pompeii and Herculaneum. The decline and desertion were probably due to changes in local land drainage patterns, leading to swampy malarial conditions (this is difficult to picture, with the present aridity; the site is now home to lizards and tourists).