The main reason for the establishment of the League of Nations was to promote peace and prevent future conflicts following the devastation of World War I. The League aimed to create a framework for international cooperation and dialogue, hoping to address disputes between nations before they escalated into war. It was also a response to the widespread desire for stability and security in a post-war world, as many nations recognized the need for collective action against aggression. Although ultimately unsuccessful in preventing World War II, the League laid the groundwork for later international organizations, including the United Nations, which continued the pursuit of global peace and security.