The Prime Minister of the Hungarian portion of the Austro-Hungarian Empire was very hesitant to declare war on Serbia but agreed to the war when Germany promised that the Austro-Hungarians would not be responsible for lands they did not want.
The Central Powers, which included the German, Ottoman and Austro-Hungarian Empires, lost World War I, and that loss formally ended the Austro-Hungarian Empire. The Habsburg Monarchy was overthrown, and Hungary formally declared its independence from Austria. Hungary lost 72% of its land under the Treaty of Trianon, which was the peace document between Hungary and the Allied powers that drew the borders of Hungary into country that we see on maps today. This map redrawing is still a very present part of Hungary today, most notably because of the Transylvanian region’s succession to the Kingdom of Romania, which had been on the side of the Allies in WWI.
Transylvania and other regions surrounding Hungary to the north, south and east (areas in what are currently Slovakia, Serbia, Slovenia, Croatia and Ukraine) had been historically and culturally part of Hungary since the earliest days of Hungary’s existence. Hungary felt these areas should belong within their borders, as they were culturally, linguistically, and in some cases ethnically Hungarian. This was ignored, and to this day, there are many Hungarian-speaking areas of Serbia, Slovakia, Romania, Slovakia, Croatia and Ukraine along the regions that border Hungary.
This serious and significant loss of natural resources, land and cultural heritage caused a deep resentment to grow within Hungary during the decades following the Treaty of Trianon.
