This essay is not intended to be comprehensive; rather, it gives readers a general idea of the five major Eurasian legal systems (Rome, Greece, the Near East, India, China) in their historical and political contexts. It also examines, briefly, the different stages of a typical legal case in each system; and because my main area of specialization is Greek law, and the Athenian legal system may be unfamiliar to many readers, I discuss it in somewhat more detail. My main thesis is that legal systems develop to meet the political needs of their communities. To illustrate this I contrast the legal systems of the two major ancient empires, Rome and China, with that of the much smaller Athenian political community, the polis.