 At the end of 1918, a Serbian Army mission led by Milan Pribićević, Dušan Simović and Milisav Antonijević arrived in Zagreb to lead the re-organisation of the Serbian Army and the National Army of Slovenes, Croats and Serbs into a single new Army of the Kingdom of Serbs, Croats and Slovenes (KSCS).By 1 January 1919, a total of 134 former high-ranking Austro-Hungarian officers had been retired or relieved of their duties.From late 1918 until 10 September 1919, the new army was involved in a sharp military confrontation with irregular pro-Austrian formations in the region of Carinthia on the northern frontier of the new KSCS.