Historians have voiced quite different opinions about the influence that the royal courts of the Hellenistic east had on the development of the Roman imperial court. This chapter considers this question, emphasizing the methodological challenges involved in identifying when one court has influenced another. After an outline of the major characteristics of the Hellenistic empires and the courts at their hearts, the focus is on the similarity of the problems faced by Hellenistic and Roman imperial leaders in the eastern Mediterranean, and on the two functions of the court that developed in response to this diversity: the court as a centre for the production of imperial, ‘cosmopolitan’ culture and as an instrument of elite integration. The chapter argues that Hellenistic influence on Roman court culture should be seen primarily in the Roman adoption of Hellenistic forms of court ritual and ideology.