The Treaty of Trianon, signed in 1920 after World War I, had a devastating impact on Hungary. The treaty resulted in Hungary losing approximately two-thirds of its territory and a significant portion of its population, as many ethnic minorities were ceded to neighboring countries like Romania, Czechoslovakia, and Yugoslavia. This territorial loss fueled nationalist sentiments and contributed to long-term political instability in Hungary, as it struggled with its identity and the sense of injustice. The sociopolitical consequences of Trianon continued to affect Hungary's relations with its neighbors for decades.