This dissertation examines how Rome and China simultaneously developed their ethnographic knowledge of the world beyond their borders, spanning from the Mediterranean to China. This occurred during the nearly simultaneous imperial expansions of both empires between the 2nd century BCE and the 3rd century CE. Part I focuses on Bactria as a converging ground in which common ethnographic knowledge between Rome and China took place. Chapter 1 examines Bactria as a cipher for the imperial expansion and desire for an expanding Roman regime from the mid-republic to the Augustan age. I argue that while Greco-Latin authors under Roman rule developed their idiosyncratic understanding of Bactria, their writings on Bactria coincide with Rome’s imperial expansion from Greece to the eastern Mediterranean and beyond. Moreover, I highlight the way Hellenistic imperialism in Central Asia, from Antiochus III to Indo-Greek kingdoms, served as the political basis for Greco-Roman ethnographic knowledge of Bactria. Chapter 2 interprets Sima Qian’s report on Hellenistic Asia, especially Bactria, within the context of Chinese intellectual debates about the political economy during the late 2nd century and the early 1st century BCE. I emphasize that China’s engagement with the nomadic political economic system is the background of Sima Qian’s representation of late Hellenistic Asia. In particular, I demonstrate the way Sima Qian rethinks the relationship between nomadic and sedentary areas through outside cases by using the knowledge of the late Hellenistic world. Part II considers performance as an identifiable carrier of ethnographic knowledge in Rome and China. Chapter 3 discusses pantomime-dominated Roman theater as the institutional mechanism through which Rome imagined former Hellenistic Asia from Syria to Bactria/India as an entity. I suggest that the development of pantomime performance, especially the growing importance of pantomime dancers, affected ethnographic knowledge production. In turn, chapter 4 highlights the agency of wandering performers (from both the Mediterranean and Central Asia) in shaping Chinese knowledge of Rome. I argue that Chinese knowledge of Rome derived from popular narratives of Roman state power on the Indian Ocean. I also highlight that Homeric motives were employed to craft relevant narratives.