In 133 BC, the last Greek king of the Hellenistic city of Pergamun bequeathed his kingdom to the Roman people. The Romans initially maintained the local coinage and probably the closed currency system that existed in the area as well. Considerations of profit apart, the Romans tended not to introduce Roman coinage automatically in newly conquered areas. Cistophori, the local royal coinage so named because of its design featuring a sacred cista (chest), continued to be made in a number of cities in the area until 68 BC.After a break of ten years, production resumed with coins made in the names of the Roman governors. One of these new cistophori was equivalent to three Roman denarii. In the Roman imperial period (from 31 BC), cistophori continued to be struck occasionally until the reign of Septimius Severus (AD 193-211) but their appearance changed. Roman designs and Latin legends replaced the previously standard Pergamene type with the emperor's head prominently portrayed on the obverse (front).The first Roman emperor, Augustus (ruled 31 BC-AD 14), in particular took the opportunity for personal advertisement on the reverse types. A sphinx appears on this issue, the device Augustus used on his signet ring during the early years of his rule.