As with most of the Ptolemaic system, the office was retained after the Roman takeover in 30 BC, with a layer of Roman officials under the augustal prefect grafted onto the existing administrative structure. The office remained important, although it apparently lost any military responsibility; very soon, it came to be held by Roman citizens of equestrian status. Reflecting the Roman division of Egypt in three broad areas (the Nile Delta area or Lower Egypt, Middle Egypt or Heptanomis, and the Thebaid), during the Roman era there were three or four epistrategoi, as there were often two holders of the office in Lower Egypt, one for the east and one for the west.