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.
Traditional international law is a law of power, that is the war is considered to be an important attribute of state sovereignty. One of the essential qualitative differences between traditional international law and contemporary international law is the prohibition of aggressive wars and the idea of international protection of human rights. In other words, contemporary international law takes the rights of man under its patronage.