The Pompeian Era was a calendar era used by Hellenistic cities in Roman Palestine, in particular the cities of the Decapolis. The calendar counted the years from the region's conquest by the Roman general Pompey in 63 BCE. Many of these cities had been self-governing poleis before the Jewish Hasmoneans had conquered them in the 2nd century BCE. The Romans restored their self-governing status, so the conquest amounted to a "new foundation" of the cities, and they made that date the epochal year of their calendars. Some other nearby cities, such as Philadelphia, adopted the era even though they had never been under Hasmonean rule.