Why was a separate Roman praetor appointed to handle cases involving foreigners?

In approximately 242 BCE, the Roman Republic established the office of the praetor peregrinus to handle legal suits involving foreigners, while the original praetor—renamed praetor urbanus—continued to preside over cases between Roman citizens.1

This separation was necessary because the existing jus civile (civil law) applied exclusively to Roman citizens and was characterized by a cumbersome formalism that was ill-suited for non-citizens. Furthermore, the Roman principle of personality originally dictated that the law of the state applied only to its citizens, leaving foreigners without legal rights unless protected by specific treaties.2

As Rome’s commercial interests expanded, the state was compelled to provide a form of justice for the foreigners within its borders. The praetor peregrinus administered a flexible alternative known as jus gentium (law of nations). This system incorporated existing Mediterranean mercantile law, simplified Roman legal institutions, and the magistrate’s own sense of equity and fairness, ensuring that justice could be applied universally to both citizens and foreigners.2