The National Football League is established, as the American Professional Football Association. September 20 – The first soldier joins El Tercio de Extranjeros (the "Regiment of Foreigners", later the Spanish Legion). Under the command of José Millán Astray and Francisco Franco, its first duties are against Rif rebels in the Spanish protectorate in Morocco. September 21 – The Communist Party of Uruguay is founded. September 25 – The Treaty of Seeb is signed, ending the Muscat rebellion and granting the Imamate of Oman Autonomy from the Sultanate of Muscat and Oman. September 22 – The London Metropolitan Police forms the Flying Squad, a motorised mobile detective patrol unit. September 27 – Polish–Soviet War: Soviet Russia sues for peace with Poland. September 29 The first domestic radio sets come to stores in the United States; a Westinghouse radio costs $10. Adolf Hitler makes his first public appearance in Austria, with speeches in Vienna, Innsbruck and Salzburg. October October 3 – The Prix de l'Arc de Triomphe horse race first runs in Paris. October 4 – The Mannerheim League for Child Welfare, a Finnish non-governmental organization, is founded on the initiative of Sophie Mannerheim. October 9 – Polish–Lithuanian War: Polish troops take Vilnius. October 10 – Carinthian Plebiscite: A large part of Carinthia Province votes to become part of Austria, rather than Yugoslavia. October 14 – A peace treaty between the Soviet and the Finnish governments is concluded at Tartu. October 16 – Polish–Soviet War: After the Polish army captures Tarnopol, Dubno, Minsk and Dryssa, the ceasefire is enforced. October 18 – Thousands of unemployed demonstrate in London; 50 are injured. October 26 – Álvaro Obregón is announced as the elected president of Mexico. October 27 The League of Nations moves its headquarters to Geneva, Switzerland. Baron Louis De Geer the Younger becomes the new Prime Minister of Sweden. October 30 – The Communist Party of Australia is founded in Sydney. October 31 – Dr. Frederick Banting of Canada first records his insight on how to isolate insulin for the treatment of diabetes; the first successful human trial of insulin will occur 15 months later. November November 2 1920 United States presidential election: Republican U. S. Senator Warren G. Harding defeats Democratic Governor of Ohio James M. Cox and Socialist Eugene V. Debs, in the first national U.S. election in which women have the right to vote. In the United States, KDKA