C. They helped legal thinkers to create modern international law. Justinian was a ruler over the Byzantine Empire, which many consider to be the continuation of the Eastern Roman Empire. Justinian developed a code during his reign from 529 to 565 CE that gave common law across the many different parts of the empire in the Mediterranean. Justinian's code was heavily inspired the Roman twelve tables, and the codes created written law that gave equal jurisdiction and treatment to all citizens of the empire.