Comparing ancient societies allows us to observe the variety of relationships that prevailed between states — in different forms and at different scales — and their complex legal environments. This chapter explores five dimensions of this relationship. First, we examine the capacity of law to shape state power. While constitutional law, strictly speaking, was comparatively rare in the ancient world, we can yet observe various ways in which law, law-like practices and other cultural norms operated collectively to both empower and constrain the state. The second and third parts of the chapter look at the inverse relationship: state power over law and legal practice in the form of legislative powers and jurisdiction, respectively. In the fourth part, we turn from ideational aspects of state law to the structure of state legal systems themselves, particularly in the context of private or non-state legal practices. Here we focus on those domains of law in which the state was most intimately engaged, what was left to non-state actors and the engagements between both across a sometimes indistinct boundary. The final part of the chapter explores the role of law in legitimizing state power.

Particularly in the context of public law, comparative law scholarship typically involves a comparison of legal norms, principles, actors, or legal institutions in different state jurisdictions or across legal traditions. The rise and increasing prevalence of transnational regulators – particularly transnational non-state regulators, but also hybrid and intergovernmental varieties – challenges this methodological default. It invites us to consider the nature of regulation across different legal regimes, some of which might be overlapping, and which, in their claims to authority, might be complementary or conflictual. Acknowledging the presence of transnational regulators within a plurality of legal orders raises questions about how state-centric regulatory institutions at the sub-national, national, regional, or international levels differ from hybrid (state/non-state) and predominantly non-state regimes, whether in terms of their functions (e.g., in terms of standard-setting, enforcement, and dispute resolution) or in terms of their relative claims to authority and political legitimacy. This chapter shows how transnational law poses a conceptual and methodological challenge for comparative lawyers, yet one that reinforces recent innovations in the comparative law field, reflected in this Handbook, that extend comparative law beyond functional comparisons of rules, legal systems, or legal traditions.