Austria-Hungary or Austro-Hungarian Empire was a vast and important European state , successor to the Austrian Empire . Resulted from a compromise between the Austrian and Hungarian nobility in 1867 , and was dissolved in 1918 , after its defeat in World War I, as per the requirements of the Treaty of Versailles implemented treaties of Saint - Germain and Trianon .
At the time of its dissolution , the empire had a total area of 677,546 km ² . Its population before the start of the First World War was estimated at 52.5 million inhabitants. What remains of this ancient state is divided between current thirteen countries : Austria, Hungary , Czech Republic , Slovakia , Slovenia , Croatia , Bosnia and Herzegovina and the region of Vojvodina , Serbia , Mouths of Kotor , Montenegro , Trentino -Alto Tyrol and Trieste in Italy, part of Transylvania and Banat , Romania , Galicia , Poland and Ruthenia ( Subcarpática region ) , Ukraine .
The largest cities in number of inhabitants in 1910 were Vienna ( 2.031 million ) , Budapest ( 882 000 ) , Prague ( 224 000 ) , Lemberg ( Lviv ) ( 206 000 ) , Trieste ( 161 000 ) , Graz ( 152 000 ) , Brünn ( Brno ) ( 126 000 ) , Krakow ( 90 000 ) , Czernowitz ( Chernivtsi ) ( 87 000 ) and Agram ( Zagreb ) ( 80 000 )