During the interwar period, the League of Nations played a pivotal role in promoting peace and cooperation among countries. Established after World War I by the Treaty of Versailles in 1919, the League aimed to prevent further conflicts through diplomacy and collective security. It facilitated discussions on international disputes, conducted humanitarian efforts, and set mandates for former territories of defeated powers. However, the League ultimately struggled with enforcement, as key nations, including the United States, did not join. Its inability to prevent aggression from countries like Germany and Japan contributed to its dissolution and the eventual outbreak of World War II.