[224] Save for a two-week return to the United States, Wilson remained in Europe for six months, where he focused on reaching a peace treaty to formally end the war. Wilson, British Prime Minister David Lloyd George, French Prime Minister Georges Clemenceau, and Italian Prime Minister Vittorio Emanuele Orlando made up the "Big Four", the Allied leaders with the most influence at the Paris Peace Conference.[225] Wilson had an illness during the conference, and some experts believe the Spanish flu was the cause.[226]
Unlike other Allied leaders, Wilson did not seek territorial gains or material concessions from the Central Powers. His chief goal was the establishment of the League of Nations, which he saw as the "keystone of the whole programme".[227] Wilson himself presided over the committee that drafted the Covenant of the League of Nations.[228] The covenant bound members to respect freedom of religion, treat racial minorities fairly, and peacefully settle disputes through organizations like the Permanent Court of International Justice. Article X of the League Covenant required all nations to defend League members against external aggression.