On the 23rd July 1914, Austria-Hungary issued an ultimatum to Serbia specifically designed to be rejected and lead to war between the two countries.

Attended by the “Big Three” Allied leaders, the conference saw United States President Franklin D. Roosevelt, British Prime Minister Winston Churchill and Soviet Premier Joseph Stalin meet to discuss the government of post-war Europe.

Roosevelt announced the establishment of formal diplomatic relations with the USSR on 16 November, and appointed William C. Bullitt as the first Ambassador to the Soviet Union.