1918 protest in Zagreb
On 5 December 1918, four days after the proclamation of the Kingdom of Serbs, Croats and Slovenes, the National Guards (an armed force of the National Council of the State of Slovenes, Croats and Serbs) and Sokol volunteers suppressed a protest and engaged in an armed clash against the soldiers of the 25th Regiment of the Royal Croatian Home Guard and the 53rd Regiment of the former Austro-Hungarian Common Army. National Guardsmen stopped the soldiers at the Ban Jelačić Square in Zagreb.