This chapter presents an analytical framework that draws upon the economics of personal and real rights, which helps in understanding the institutions of the Roman familia. The discussion proceeds in four stages. First, it outlines the central tenets of the theory, which regards the formalization of transactions as a critical, secondary, public “contractual” step for creating a tradable legal commodity, specifically robust property (real) rights that are enforceable in rem against everyone but do not increase transaction costs. Second, it applies the theory to the marriage contract, a fundamental component of family law. Third, the chapter examines some of the primary features of Roman personal contracting from this analytical perspective, particularly the standard transactions related to the Roman familia, which is better comprehended as a household than as a mere family. Lastly, it focuses on one of the main features of Roman family law: the dowry, explaining the tendency to enforce it as a right in rem.