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Ius Gentium, the First International Law System

Updated: Aug 19, 2022

History has given us so much to date. It has given us democracy, the human rights we enjoy, the states we live in and so much more. And one of the biggest contributors to us from history were the Romans. The legal field of International Law would have zero resemblance to what we see today if it wasn’t for the Romans and their concept of Jus Gentium. In fact, the phrase International Law was a replacement for the term Law of Nations, a translation of Jus Gentium.

Jus Gentium, Latin for ‘Law of Nations’, was originally designed as a form of Natural Law by the Romans. Natural Law, when distinguished from Civil Law, is the laws that are brought about by natural reason. Therefore, it applies to all people, no matter what state. It was believed at the time that any law that is common to all people in all states must be just and valid.

The Jus Gentium was originally created to fix an age-old problem, inter-state relations. The laws of the time stated, under the Principle of Personality, that only citizens of a particular state were given any sort of rights under that state or had the laws of that state apply to them. Therefore, in theory, any Roman could have taken the property and even the life of any foreigner they saw, should they be within Roman city-state boundaries. Of course, this was a problem, as it hampered any sort of trade between cities and stopped the punishing of wrongdoers who did not live in Rome. This could be fixed through things such as treaties of mutual protection, but not all city-states had these treaties with Rome, so laws concerning foreigners had to be created. These laws would also have to be as efficient as possible, to aid in trade, as most foreigners would not be happy with the extent of formalities in classic Roman Civil Law.

Why is this ancient set of laws relevant you ask? Well, The Jus Gentium was the very first of a set of laws that guaranteed foreigners certain rights once they entered another city-state. This was a completely new idea at the time. This set of laws are the only reason trade can be as globalized as it is today and the world can be so ‘small’ as the old saying goes. In fact, it birthed the concept of international human rights laws. Because of Jus Gentium, refugees of conflicts can safely flee to another country and have their rights protected by that country. So, as is so often the case, the Roman hand is still visible in our time and shall be for centuries.

Encyclopedia Brittanica, 2018. Jus Gentium - Roman Law. [Online] Available at: [Accessed 25th June 2021].

Encyclopedia Brittanica, 2018. Roman Law. [Online] Available at: [Accessed 25 June 2021].


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