When Julius Caesar crossed the Rubicon in 49 BCE and initiated the transformation of the Roman Republic into the Roman Empire, he was not merely changing the form of Roman governance. He was accelerating the development of the most comprehensive legal system the ancient world had yet produced — a system that would, through the Byzantine Empire and then through the Catholic Church and then through the European colonial powers, become the foundation of the international legal order that governs the world today. The Roman legal system is not ancient history. It is the bedrock on which contemporary law is built, and understanding it is essential to understanding how the rights claims of African and Indigenous peoples have been structured, denied and asserted across five centuries of colonial and post-colonial legal contestation.

The Roman legal concept most directly relevant to the history of colonial law is the persona — the legal mask. In Roman law, a persona was not a person. It was a legal category that determined what rights and obligations a particular individual could exercise. Roman citizenship conferred the full set of legal rights that Roman law made available. Non-citizens, freed persons, and slaves had diminished or no legal personhood. The categories were not natural; they were legal constructions. And the legal construction of diminished personhood is the mechanism through which colonial law would, fifteen centuries later, deny African and Indigenous peoples the rights that natural law traditions had always held to be inherent in humanity.

Mare Nostrum — The Sea as Legal Territory

The Roman concept of mare nostrum — our sea — was the first comprehensive assertion of imperial legal sovereignty over international waters. The Mediterranean was, in Roman legal and political theory, not an international commons but Roman territory, subject to Roman jurisdiction, policed by Roman naval power, and organized for Roman commercial and military purposes. This assertion of sovereign jurisdiction over water — over the medium of movement and trade rather than just over land — is the conceptual ancestor of the Law of the Sea conventions that govern international waters today, and of the maritime legal framework within which the Atlantic slave trade was organized and conducted.

The Roman legal framework for maritime commerce was sophisticated and comprehensive. It included rules for contracts made at sea, for the liability of ship owners for cargo, for the treatment of shipwreck, for the status of cargo abandoned at sea. The concept of jettison — the deliberate throwing overboard of cargo to save a ship — was specifically addressed in Roman maritime law. Fifteen centuries later, the owners of the slave ship Zong would use the legal concept of jettison, derived from Roman maritime law, to justify throwing 132 enslaved Africans overboard and claim their value from their insurers. The Roman law of maritime commerce became, through the Zong case, the law of the murder of enslaved African people.