Byzantine Maritime Law

You can hear the echoes of Rhodian Sea Law in the Roman legal code, the Romans themselves contributed significant legal developments. This is largely because quick, efficient, and reliable shipping was as important to Rome as it was to Rhodes or Athens.

In the reign of Emperor Gaius Caligula around 40 AD, Rome and its surrounding areas could not produce enough food to feed the population. The city was thus reliant on imported foreign food. But when this maritime food trade slowed, and people began to go hungry, there were riots. The Emperor himself was almost killed. Therefore, Caligula’s successor, Claudius, invested in Rome’s main port of Ostia. He increased its capacity to make sure that the Roman people never starved again. Shipping across the Mediterranean was also the best way to transport troops to defend the boundaries of the Roman Empire.

But physical infrastructure needed legal infrastructure alongside it for shipping in the Empire to function smoothly. Justinian, the Emperor of the Byzantine or Eastern Roman Empire between 527-565 AD, was important in formalising this Roman legal infrastructure. Justinian brought together different Roman Laws into Digests and Institutes, the best and most complete records of Roman law we have today.

In Justinian’s law books, the ‘freedom of the sea’ is a central doctrine. The Greeks had no legal word for ‘property’ or ‘dominion’, the Romans developed these legal terms. The Greeks had an idea of ‘natural ownership’ through hunting or fishing, and had other forms of ownership, but the Romans specifically defined these terms that are significant to marine law, and all other laws. Greeks and Romans alike saw the sea as a food source open to all, and one that could be owned by no single entity.

In the second century AD, Marcianus was the first jurist to write on the freedom of the sea. In the Christian era the Roman Empire stretched along the full internal coastline of the Mediterranean. Therefore, there was no foreign challenge or threat to Roman ships. Despite this, Roman law, as written by Marcianus, maintained that no state could claim ownership of the sea.

Ulpian and Celsus, two other Roman jurists, agreed the sea is res communes - ‘something owned by no-one and to use by all’. Paulus defined the limit of the shoreline by the maximum winter or flood tide, whilst Neratius and Paulus wrote that the shore itself was also res communes, like the sea. However, harbours and ports were res publicae - ‘something owned by the State’.

These contributions to Roman marine law were all built into the Justinian's Digests, or the Corpus Iuris Civilis. These texts set the standard for written bodies of law.