Since the beginning of human existence, societies have devised systems of rules to govern themselves and to regulate the behavior of the people belonging to them. When those laws are enforced by some kind of political power in a social structure bigger than a tribe, we can start talking about the existence of a state. That’s exactly what happened sometime between 3200 BC and 3100 BC in what is now Egypt. Pharaoh Narmer managed to unify all of Ancient Egypt under his power, establishing the first unified political power in history over a territory further than a village. Hence, Narmer is considered the first ruler of the first sovereign state in history.
Since then, many other sovereign states have been created, in many forms. All along history, humans have incorporated kingdoms, empires, republics, federal states or theocracies, among many other types of government.However, we had also had many instances in history of government entities that claimed to be sovereign states, and due to one reason or another, ended up not being recognised as that by the rest of the world. So a question inevitably arises: how do we know that a sovereign state is actually a sovereign state?
Traditionally, a state became sovereign when another sovereign state, especially a great power, recognized it as such. This is the so-called constitutive theory of statehood, and it became codified as a binding international law in the 1815 Congress of Vienna, held after the downfall of Napoleon and that set up the Concert of Europe, the diplomatic framework that governed Europe until World War I.