context: The study of international relations as a theory has existed since the book The Twenty Years' Crisis by E. H. Carr was published in 1939 and the book Politics Among Nations by Hans Morgenthau was published in 1948. [4] The discipline of international relations is believed to have arisen after World War I through the establishment of the post of International Relations Lecturer at the University of Wales, Aberystwyth. [5] Early international relations education in the interwar period was more concerned with replacing the balance of power system with a comprehensive security system. The thinkers of that era would later be referred to as the "Idealist" group. [6] His main criticism was conveyed through the "realist" analysis presented by Carr.
question: When was the theory of international relations created?
answers.text: 1939