Hungarian irredentism or Greater Hungary (Hungarian: Nagy-Magyarország) are irredentist political ideas concerning redemption of territories of the historical Kingdom of Hungary. The objective is to at least to regain control over Hungarian-populated areas in Hungary's neighbouring countries. Hungarian historiography uses the term "Historic Hungary" (Hungarian: történelmi Magyarország). "Whole Hungary" (Hungarian: Egész-Magyarország) is also commonly used by supporters of this ideology.
The Treaty of Trianon defined the current borders of Hungary and, compared against the claims of the pre-war Kingdom, post-Trianon Hungary had approximately 72% less land stake and about two-thirds fewer inhabitants, almost 5 million of these being of Hungarian ethnicity.[1][2] However, only 54% of the inhabitants of the pre-war Kingdom of Hungary were Hungarians before World War I.[3][4] Following the treaty's instatement, Hungarian leaders became inclined towards revoking some of its terms. This political aim gained greater attention and was a serious national concern up through the Second World War.[5]
After World War I, despite the "self-determination of peoples" idea of the Allied Powers, only one plebiscite was permitted (later known as the Sopron plebiscite) to settle disputed borders on the former territory of the Kingdom of Hungary,[6] settling a smaller territorial dispute between the First Austrian Republic and the Kingdom of Hungary, because some months earlier, the Rongyos Gárda launched a series of attacks to oust the Austrian forces that entered the area. During the plebiscite in late 1921, the polling stations were supervised by British, French, and Italian army officers of the Allied Powers.[7]
Irredentism in the 1930s led Hungary to form an alliance with Hitler's Nazi Germany. Eva S. Balogh states: "Hungary's participation in World War II resulted from a desire to revise the Treaty of Trianon so as to recover territories lost after World War I. This was the basis for Hungary's interwar foreign policy."[8]
Hungary, supported by the Axis Powers, was successful temporarily in gaining some regions of the former Kingdom by the First Vienna Award in 1938 (southern Czechoslovakia with mainly Hungarians) and the Second Vienna Award in 1940 (Northern Transylvania with an ethnically mixed population), and through military campaign gained regions of Carpathian Ruthenia in 1939 and (ethnically mixed) Bačka, Baranja, Međimurje, and Prekmurje in 1941 (Hungarian occupation of Yugoslav territories). Following the close of World War II, the borders of Hungary as defined by the Treaty of Trianon were restored, except for three Hungarian villages that were transferred to Czechoslovakia. These villages are today administratively a part of Bratislava.