Aftermath of the Austria-Hungarian Civil War
Following the Great War, Austria saw only minor expansion of its empire with Serbia and Montenegro falling under Austrian influence. However, this saw even worse ethnic tension for the empire, attempts were made to reform the empire into the United States of Great Austria, but these universally failed to come to fruition.
After the Parliament in Bosnia brought up the concept of an independence referendum, the autonomy of the province was heavily reduced, leading to the region declaring independence in 1926, encouraging all minorities to do the same. Austria was on the way to invade Bosnia as the region of Bohemia declared independence as well, followed soon by Serbia and Montenegro claiming full independence from the Austrian Crown and supporting their own rebels.
The Empire requested aid from their ally to the north, but Germany was struggling with the Red Wave in the east and couldn't spare resources that were being used to stop communism in their empire. However, the Austrian Ally of Naples was willing to send aid. The Front lines were slow and very similar to the Western Front of the Great War, until in June of 1927 when the Bosnian Lines collapsed and Bosnia was defeated. However, at that point rebels across the Empire was seeing their opportunity. Poles in Galicia, Romanians in Hungary and Italians in Lombardy-Venetia, and with these rebels came other nations supporting them.
At the arrival of Romania into the war, Bulgaria would join as they were already debating support for Austria to gain land in Serbia that had been promised but not delivered in the Great War. Tuscany would also join after the declaration of war by Sardinia-Piedmont. Romania originally saw great success in the unoccupied northern Hungary but after Bosnia surrendered, many soldiers pushed them back and with Bulgarian aid, Romania surrendered in spring of 1928; ceding the remainder of Dobrogea to Bulgaria. After the defeat of the Bohemian rebels and the great success's of the Italians, Hungary realized their opportunity and declared independence, turning their rifles on Austria.
Austria, desperate to hold on, made peace with many of the smaller rebel states. The Treaty of Venice saw the cession on Lombardy to Sardinia-Piedmont, forming the Kingdom of High Italy. The Treaty of Belgrade released Serbia and Montenegro from being Client states [To which they would unify a month later. And the Treaty of Lemberg saw Polish border regions of Galicia unified with Poland. The War between Naples and Austria versus Hungary would continue for another year and a half until the Austrians collapse from economic strain and made peace in August 4 1930, ending the Austrian Civil War.
The people of Austria were deeply wounded by the war and the death of their empire. Even after joining the European Economic Confederation the following year giving their economy a boost, they were heartbroken. However, a new movement has become popular in the eyes of the Young Austrians, that of a Union of the Germanic Kingdoms.
This map is part of my ongoing Timeline; The Lion, The Rooster and the Eagle. A Larger, full-size version can be found
here.