The 1st Army was a Royal Yugoslav Army formation commanded by Armijski đeneral Milan Rađenković during the German-led Axis invasion of the Kingdom of Yugoslavia in April 1941 during World War II. It consisted of one infantry division, one horsed cavalry division, and two brigade-strength infantry detachments. It formed part of the 2nd Army Group, and was responsible for the defence of the section of the Yugoslav-Hungarian border between the Danube and the Tisza rivers. The 1st Army was not directly attacked during the first few days after the invasion commenced, but attacks on its flanks resulted in successive orders to withdraw to the lines of the Danube and then the Sava. The Hungarians then crossed the border in the sector for which the 1st Army had been responsible, but the Yugoslavs were already withdrawing and the Hungarians faced almost no resistance. This was followed by the German capture of Belgrade and the rear area units of 1st Army. Remnants of the 1st Army continued to resist along the line of the Sava, within days, tens of thousands of Yugoslav soldiers had been captured. The Germans closed on Sarajevo, and accepted the unconditional surrender of the Royal Yugoslav Army on 17 April, which came into effect at the following day. Background The Kingdom of Serbs, Croats and Slovenes was created with the merger of Serbia, Montenegro and the South Slav-inhabited areas of Austria-Hungary on 1 December 1918, in the immediate aftermath of World War I. The Army of the Kingdom of Serbs, Croats and Slovenes was established to defend the new state. It was formed around the nucleus of the victorious Royal Serbian Army, as well as armed formations raised in regions formerly controlled by Austria-Hungary. Many former Austro-Hungarian officers and soldiers became members of the new army. From the beginning, much like other aspects of public life in the new kingdom, the army was dominated by ethnic Serbs, who saw it as a means by which to secure Serb political hegemony. The army's development was hampered by the kingdom's poor economy, and this continued during the 1920s. In 1929, King Alexander changed the name of the country to the Kingdom of Yugoslavia, at which time the army was renamed the Royal Yugoslav Army (, VKJ). The army budget remained tight, and as tensions rose across Europe during the 1930s, it became difficult to secure weapons and munitions from other