Historical roots and stages of the development of international activities of cities, their contribution to the formation of modern diplomatic principles and institutions

The article explores the historical aspects and main stages in the development of international activities of cities, which made it possible to identify four main stages characterized by different types of urban communities, the specifics of the implementation of external relations and the nature of interaction with national states. The author reveals a number of principles and prototypes of international relations and diplomatic activity, laid down in the historical eras of Antiquity and the Middle Ages, relevant in modern times.