The treaty that officially ended the First World War was the Treaty of Versailles, signed on June 28, 1919. Negotiated at the Paris Peace Conference, it primarily involved the Allied Powers, particularly the United States, France, Britain, and Italy. The treaty imposed significant territorial losses, military restrictions, and reparations on Germany, which many historians argue sowed the seeds for future conflicts, including World War II. Additionally, it created the League of Nations, aiming to promote peace and prevent future wars. The harsh terms of the treaty and the ensuing economic hardship in Germany contributed to political instability and resentment.