Kingdom of Serbs, Croats and Slovenes. The provincial government of Styria, which had not supported these actions, subsequently issued a warrant ordering Mikl's arrest for treason. When the Treaty of Saint-Germain-en-Laye was signed later in 1919, Radkersburg was retained within what became the First Austrian Republic. In 1920, Mikl was accepted by the new Austrian Army (), joining the 11th Alpenjäger Regiment. During 1920–21 he was rapidly promoted to Hauptmann (captain), and on 20 October 1920 he was posted to the 5th Cyclist Battalion in Villach, Carinthia. In 1921, his battalion was deployed to Burgenland to assist in the transfer of that region from Hungary to Austria. In 1922, he changed his name to the more Germanised Mickl. On 2 May 1922, Mickl married Helene Zischka in Klagenfurt; their only child, Manfred, was born in 1923. That same year, he was promoted to the rank of Major. In 1925, Mickl passed the examinations for the general staff. On 26 July 1930, Mickl was appointed an honorary citizen of the town of Radkersburg. After fifteen years with the 5th Cyclist Battalion, in 1934, Mickl briefly served on the military headquarters for Carinthia in Klagenfurt. In February of the following year, he was posted to the headquarters of the 3rd Brigade at Sankt Pölten. His promotion to Oberstleutnant (lieutenant colonel) followed in 1936. In the same year, Mickl's son Manfred entered the military cadet school at Enns. On 14 March 1938, following the Anschluss, Mickl was absorbed at his rank into the German Army, but as a troop officer, not a general staff officer. From 12 May to mid-August 1938, he attended training at the Panzertruppenschule II (Armoured Troops School No. 2) in Wünsdorf south of Berlin, before being given command of the 42nd Panzerjäger (Anti-tank) Battalion of the 2nd Light Division. Helene soon moved to Gera in Thuringia to join Mickl, leaving the 15-year-old Manfred at the cadet school until his graduation. World War II Invasions of Poland and France Mickl commanded the 42nd Panzerjäger Battalion of Generall Georg Stumme's 2nd Light Division during the September 1939 invasion of Poland, during which the division was involved in difficult fighting through Kielce and Radom in central Poland to Modlin on the Vistula. The following month, Mickl was awarded the Iron Cross 2nd Class. During the winter of 1939/40, the 2nd Light Division was reclassified and converted into the 7th Panzer Division, in