The 1st Cavalry Division of the Royal Yugoslav Army was established in 1921, soon after the creation of the Kingdom of Serbs, Croats and Slovenes, which became the Kingdom of Yugoslavia in 1929. In peacetime it consisted of two cavalry brigade headquarters commanding a total of four regiments. It was part of the Yugoslav 1st Army Group during the German-led World War II Axis invasion of Yugoslavia in April 1941, with a wartime organisation specifying one cavalry brigade headquarters commanding two or three regiments, and divisional-level combat and support units.