World War II: The Nazi-affiliated Ustaše is put in charge of the Independent State of Croatia by the Axis powers after Operation 25 is effected.
The invasion of Yugoslavia, also known as the April War or Operation 25, was a German-led attack on the Kingdom of Yugoslavia by the Axis powers which began on 6 April 1941 during World War II. The order for the invasion was put forward in "Fhrer Directive No. 25", which Adolf Hitler issued on 27 March 1941, following a Yugoslav coup d'tat that overthrew the pro-Axis government.The invasion commenced with an overwhelming air attack on Belgrade and facilities of the Royal Yugoslav Air Force (VVKJ) by the Luftwaffe (German Air Force) and attacks by German land forces from southwestern Bulgaria. These attacks were followed by German thrusts from Romania, Hungary and the Ostmark (modern-day Austria, then part of Germany). Italian forces were limited to air and artillery attacks until 11 April, when the Italian army attacked towards Ljubljana (in modern-day Slovenia) and through Istria and Lika and down the Dalmatian coast. On the same day, Hungarian forces entered Yugoslav Baka and Baranya, but like the Italians they faced practically no resistance. A Yugoslav attack into the northern parts of the Italian protectorate of Albania met with initial success, but was inconsequential due to the collapse of the rest of the Yugoslav forces.
Scholars have proposed several theories for the Royal Yugoslav Army's sudden collapse, including poor training and equipment, generals eager to secure a quick cessation of hostilities, and Croatian, Slovenian, and ethnic German fifth column activities. The latter has been questioned by scholars who have suggested that the fifth column had little effect on the ultimate outcome. The invasion ended when an armistice was signed on 17 April 1941, based on the unconditional surrender of the Yugoslav army, which came into effect at noon on 18 April. The Kingdom of Yugoslavia was then occupied and partitioned by the Axis powers. Most of Serbia and the Banat became a German zone of occupation while other areas of Yugoslavia were annexed by neighboring Axis countries, Germany, Hungary, Italy, Albania and Bulgaria. Croatia became the Independent State of Croatia (Serbo-Croatian Latin: Nezavisna Drava Hrvatska, or NDH), an Axis puppet state created during the invasion comprising the Srem, Bosnia and Herzegovina as well as the Croatian lands. Along with Italy's stalled invasion of Greece on 28 October 1940, and the German-led invasion of Greece (Operation Marita) and invasion of Crete (Operation Merkur), the invasion of Yugoslavia was part of the German Balkan Campaign (German: Balkanfeldzug).
The Ustaše (pronounced [ûstaʃe]), also known by anglicised versions Ustasha or Ustashe, was a Croatian fascist and ultranationalist organization active, as one organization, between 1929 and 1945, formally known as the Ustaša – Croatian Revolutionary Movement (Croatian: Ustaša – Hrvatski revolucionarni pokret). Its members murdered hundreds of thousands of Serbs, Jews, and Roma as well as political dissidents in Yugoslavia during World War II.The ideology of the movement was a blend of fascism, Roman Catholicism and Croatian nationalism. The Ustaše supported the creation of a Greater Croatia that would span the Drina River and extend to the border of Belgrade. The movement emphasized the need for a racially "pure" Croatia and promoted genocide against Serbs—due to the Ustaše's beliefs grounded in anti-Serb sentiment—and Jews and Roma via Nazi racial theory, and persecution of anti-fascist or dissident Croats and Bosniaks. The Ustaše viewed the Bosniaks as "Muslim Croats", and as a result, Bosniaks were not persecuted on the basis of race.Fiercely Roman Catholic, the Ustaše espoused Roman Catholicism and Islam as the religions of the Croats and Bosniaks and condemned Orthodox Christianity, which was the main religion of the Serbs. Roman Catholicism was identified with Croatian nationalism, while Islam, which had a large following in Bosnia and Herzegovina, was praised by the Ustaše as the religion that "keeps true the blood of Croats."It was founded as a nationalist organization that sought to create an independent Croatian state. When the Ustaše came to power in the Independent State of Croatia (NDH), a quasi-protectorate puppet state established by Fascist Italy and Nazi Germany during World War II, its military wings became the Croatian Home Guard and the Ustaše Militia (Croatian: Ustaška vojnica). However, the Ustaše lacked support among ordinary Croats and never accrued any significant support among the populace. The Ustaše regime was backed by parts of the Croat population that during the interwar period had felt oppressed in the Serb-led Yugoslavia. Most of the support it had initially gained by creating a Croat national state was lost because of the brutal practices it used.The movement functioned as a terrorist organization before World War II but in April 1941, they were appointed to rule a part of Axis-occupied Yugoslavia as the NDH, which has been described as both an Italian-German quasi-protectorate, and as a puppet state of Nazi Germany.