The Austro-Hungarian Civil War was an armed conflict that arouse from the aftermath of the Great War and is generally considered an extension of the Eastern Crisis. The war arouse from large anti-Hapsburg sentiment throughout the Hapsburg domains and from growing separatist aspirations among the multicultural empire's non-German communities. The war ended in 1922 with the Peace of Vienna which broke up the old Hapsburg Empire.
The Austro-Hungarian Empire was created from the Compromise of 1867 in the aftermath of the Austro-Prussian War. The new state was built on the premise of two separate states ruled by the same crown in a dual-monarchy. This compromise worked for a time. However, by the start of the great War in 1914 Austrian Germans and Hungarians made up only 44% of the population while they controlled a majority of its power. This led to a rise in nationalism and separatism throughout the country which further destabilized the political structure.
To counter growing nationalism, the conservatives granted some concessions to the Czechs, stimulated the development of a Ukrainian national identity to counter Polish national aspirations and instituted a policy of Germanization of the Empire's diverse ethnic groups. However, all of these efforts failed to curb growing nationalism and only helped weaken Hungarian-Austrian unity.
As the 19th century came to an end and the 20th century began the government faced increased political division as the Germans became divided along political ideals with Liberals, and German Nationalists hoped to suppress and eventually Germanize the Empire's other ethnic groups producing larger ethnic tensions. Slavic nationalism fueled by Russian and Serbian national aspirations and by the growing cultural and political demands of the Czechs, Slovaks, Poles, and Romanians only added fuel to the fire.
The outbreak of the Great War after the assassination of Archduke Charles would prove the breaking point for the Empire as it became increasingly dependent upon Germany throughout the war. Suffering a series of defeats at the hands of Russia early on due to poor communication between the central powers lead to a series of setbacks that would eventually be overturned, however, at the expense of Austria-Hungary's capacity to wage war independently of Germany. Disagreements between Hungarian and Austrian governments over recruitment and responsibilities further undermined the Nation's capabilities to wage war.
As the war drew to an end with the collapse of Russia, Serbia and Romania, the Austro-Hungarian Empire found itself on the winning side. However, it was overstretched having to provide large amounts of troops to help hold down the newly occupied territories and suffered from increasing shortages of men due to heavy losses during the war on several fronts. The chronic shortage of men was only increased by the refusal to enlist and draft dodging. A large number of the armed forces was also of different nationalities and were generally sympathetic to the separatist causes. Anti-war protests also grew as the blockade and general conscription crippled the national economy and food production. Socialist, Liberal and other left wing groups were gaining sway over the general populace.
As a result of American mediation and growing ethnic troubles, Vienna agreed to grant over a period of six years increased autonomy and freedom to its subjects. The Germans had little real plans to do so as they felt that they would lose their status as the empire's elite. Emperor Karl I tried to push forward reforms which would have turned the empire into a multicultural confederation but ultimately failed as he was unable to reconcile German nationalists with Separatists. Ethnic violence and political unrest started growing. Trouble truly began when Czech, Hungarian, South Slavs and Polish activists began demanding independence while socialist and worker protests broke out in Vienna and Budapest for protection of workers rights and an end to Austrian Involvement in the occupation of Eastern Europe.
Initially, Karl I tried to negotiate with the protesters and nationalist groups. However, his attempts were blocked by the Austrian Military and by the dominant German elite, not to mention the pressure he faced from Berlin to put an end to the growing unrest.
The visibility of political division and delayed talks in the capital led to further dissidence within the state and large scale protests broke out in major cities across the country and in occupied Northern Italy. Things continued to escalate until June 1919 when Imperial forces opened fire on protesters in Prague and Sarajevo, killing 500 people in total. The massacres provoked even larger demonstrations and a surge of violence against ethnic Germans throughout the country.
Efforts by the central government in Vienna to calm violence only worsened things. The Imperial Council - realizing their folly - decided to support Karl's reforms and promised autonomy and equality in an imperial federation. However, these efforts came too late as separatist movements were now widespread throughout the country.
The army and police were able to hold down the unrest until September 9th when left wing partisans staged mass protests in Vienna marching on the Parliament and Royal Palace. The Partisans met with Imperial troops and fighting ensued which resulted in Bloody Tuesday. The bloodshed in Vienna led to Communist uprisings and an outbreak of political violence in other major cities of Austrian proper and in Bohemia. Austria-Hungary was quickly falling into disorder as the capital was dealing with the aftermath of confrontations.
Taking advantage of the uprising in Austria, Hungarian left-wing nationalists revolted in Budapest, Szeged and Debrecen on September 24th declaring the Republic of Hungary, which soon spread to the rest of Hungary. Fearful of being subjugated to Magyar domination Romanian, Croatian, and Slovakian partisans also revolted to consolidate their independence.
The revolution in Hungary lead to a large number of Hungarian soldiers defecting to the Separatist cause. Bohemia, Galicia and Bosnia remained under imperial control however nationalist aspiration were growing and Vienna was swiftly losing control of the situation. With the Government and military in a state of anarchy, Vienna called back 100,000 troops from eastern Europe to help suppress the growing insurrections.