In 395 AD, Rome split into two empires - the Western Roman Empire and the Eastern Roman Empire. Each side had a ruler in charge of it. The Roman Empire was split by Theodosius.
The First Geneva Convention (1864) is one of the earliest formulations of international law. International law is the set of rules generally regarded and accepted as binding in relations between states and between nations. It serves as a framework for the practice of stable and organized international relations.
And adapt it must. International law must meet the global challenges of the day-if it fails to do so, it risks sliding into irrelevance. International law provides an essential framework for the pursuit of our foreign policy interests.