The League of Nations, which began its work in 1920, was founded based on the idea of developing the cooperation and guarantee peace and security among nations. In order to implement this idea, there was emphasis for the need of states to make commitments not to resort to war and to adhere strictly to the rules of international law recognized as binding standards of actions of governments.
The League of Nations also performed other social and cultural tasks. A specific problem was that the League of Nations was conceived from the beginning as an institution dependent on factual international development, on the approach of individual states and on the mutual balance of forces between them.
However, the contribution of the League of Nations is, that it was the first international organization to represent a system of collective security. The paper evaluates the importance of the League of Nations for the development of international law in terms of its pros and cons.