The concept of sovereignty was popularized by Jean Bodin. He was a French jurist and political philosopher who lived in the 16th century. Bodin believed that the state should have supreme power or authority within its own territory, which he referred to as "sovereignty." This means that the state should be free from external interference in its internal affairs. The concept of sovereignty has since become a fundamental principle of modern political theory, and is seen as a key component of the nation-state.