Problem setting. An international treaty is an agreement between two or more subjects of international relations concerning the establishment, modification or termination of mutual rights and obligations. In modern time an international treaty is the universal and primary source of international law and, at the same time, the law of treaties as a branch of international law occupies a central place in this system. The role of the treaty is constantly increasing, so it is important to study how treaty law was formed in order to understand how it has changed over history, and what factors have influenced the formation of the main branch of international law.
Analysis of recent researches and publications. The law of international treaties causes increased attention of lawyers to the study, research and analysis of its main aspects. Among the domestic and foreign scholars who have made a significant contribution to the study of the law of treaties can be distinguished such as V. Butkevich, Y. Brownlie, A. Talalaev, O. Merezhko, O. Nazarenko, F. Martens, V. Shurshalov, I. Lukashuk, O. Zadorozhniy and others.
Target of research. Study of international treaty at different stages of formation of international law, analysis and comparison of forms, content, functions and significance of the treaty in different historical periods.
Article’s main body. The article is devoted to the development and formation of the basic branch of international law – treaty law. It studies the stages of formation of the institute of treaty law during different periods of history, identifies the features of the treaty at each stage of formation.
Conclusions and prospects for the development. The agreement is an important and necessary instrument of interaction and communication between people, it establishes ties between peoples and states, helps to resolve conflicts, that is why the signing of treaties is a significant mechanism for the regulation of human relations since ancient times. In this article we have traced how different historical periods influenced the formation of international treaty law, which events were of key importance for the development of international law in general. Throughout the history of international law, the treaty has undergone a number of transformations of its forms, types and procedures of conclusion. The treaty form of consolidation of international relations is the basis of stability and efficiency of the legal order in international law. At the present time, the law of international treaties is a self-sufficient, developed branch and system of international law. It is the key branch of international law with its institutions, low basic principles, and continues to develop rapidly and irreversibly.
VII.—On the Use of the Term Neocomian