What is sovereignty in a democracy?

Sovereignty is the quality of having supreme, independent authority over a territory. It can be found in a power to rule and make law that rests on a political fact for which no purely legal explanation can be provided. The concept has been discussed, debated and questioned throughout history, from the time of the Romans through to the present day, although it has changed in its definition, concept, and application throughout, especially during the Age of Enlightenment. The current notion of state sovereignty was laid down in the Treaty of Westphalia (1648), which, in relation to states, codified the basic principles of territorial integrity, border inviolability, and supremacy of the state (rather than the Church). A sovereignty is a supreme lawmaking authority.