Who declared that Germany and Austria were responsible for starting world war 1?

The blame for the outbreak of World War I was primarily assigned to Germany and Austria-Hungary in the Treaty of Versailles, signed in 1919. The treaty included a "war guilt clause" (Article 231) that placed responsibility for the war on Germany and its allies. This declaration was influenced by the Allied powers, particularly France and Britain, who sought to justify reparations and political consequences for the Central Powers following their defeat in the war.