4 – Inauguration of Warren G. Harding as 29th President of the United States. March 5 – Irish War of Independence: Clonbanin ambush: A force of about 100 Irish Republican Army members attacks a British Army convoy of 40 soldiers, killing several, including Brigadier General Cumming. March 8 Spanish Premier Eduardo Dato e Iradier is assassinated while exiting the parliament building in Madrid. Allied forces occupy Düsseldorf, Ruhrort and Duisburg. March 9 – Cilicia Peace Treaty is signed between the French Third Republic and the Turkish National Movement in an attempt to end the Franco-Turkish War. March 12 – The İstiklâl Marşı (Independence March), the Turkish national anthem, is officially adopted. March 13 – Occupation of Mongolia: The Russian White Army captures Mongolia from China; Roman von Ungern-Sternberg declares himself ruler. March 14 – Armenian Soghomon Tehlirian assassinates Mehmed Talaat, former Interior Minister of the Ottoman Empire, in Charlottenburg, Berlin. March 16 Treaty of Moscow establishes friendly relations between the Government of the Grand National Assembly of Turkey and the Russian Socialist Federative Soviet Republic. Six Irish Republican Army men of the Forgotten Ten are hanged in Mountjoy Prison, Dublin. March 17 The Red Army crushes the Kronstadt rebellion, and a number of sailors flee to Finland. Dr. Marie Stopes opens the first birth control clinic in the British Empire in London, UK. The Second Polish Republic adopts the March Constitution. March 18 – The second Peace of Riga ends the Polish–Soviet War. A permanent border is established between the Polish and Soviet states. March 20 – Upper Silesia votes for re-annexation to Germany. March 21 The New Economic Policy starts in Soviet Russia. Irish War of Independence: Headford Ambush – The Irish Republican Army kills at least 9 British Army troops. March 24 – The 1921 Women's Olympiad (the first international women's sports event) begins in Monte Carlo. March 31 Abkhazia becomes the Socialist Soviet Republic of Abkhazia. The British government formally returns the coal mines from wartime control to their private owners, who demand wage cuts; in response, the Miners' Federation of Great Britain calls on its partner trade unions in the Triple Alliance to join it in strike action, leading in turn to the government declaring a state of emergency for the first time under the Emergency Powers Act 1920. On April 1, a lockout of striking coal miners begins. April April 11 – The Emirate of