Hungary loses 71% of its territory and 63% of its population when the Treaty of Trianon is signed in Paris.
The Treaty of Trianon (French: Traité de Trianon, Hungarian: Trianoni békeszerződés) was prepared at the Paris Peace Conference and was signed in the Grand Trianon château in Versailles on 4 June 1920. It formally ended World War I between most of the Allies of World War I and the Kingdom of Hungary. French diplomats played the major role in designing the treaty, with a mind to establishing a French-led coalition of the newly formed states. It regulated the status of the Kingdom of Hungary and defined its borders generally within the ceasefire lines established in November–December 1918 and left Hungary as a landlocked state that included 93,073 square kilometres (35,936 sq mi), 28% of the 325,411 square kilometres (125,642 sq mi) that had constituted the pre-war Kingdom of Hungary (the Hungarian half of the Austro-Hungarian monarchy). The truncated Kingdom had a population of 7.6 million, 36% compared to the pre-war kingdom's population of 20.9 million. In the last census before the Treaty of Trianon held in 1910, which recorded population by language and religion, but not by ethnicity, speakers of the Hungarian language included approximately 48% of the entire population of the Kingdom of Hungary. Though the areas that were allocated to neighbouring countries had a majority of non-Hungarians (based on the 1910 census: 54% Romanians in Transylvania, 58% Slovaks in Upper Hungary, 40% Serbo-Croatians in Vojvodina, 54% Ruthenians in Carpathian Ruthenia, 62% Croats in Croatia, 48% Italians in Fiume, 74% Germans in Őrvidék, 80% Slovenes in Muravidék), in them lived 3.3 million Hungarians – 31% – who were now in a minority status. The treaty limited Hungary's army to 35,000 officers and men, and the Austro-Hungarian Navy ceased to exist. These decisions and their consequences have been the cause of deep resentment in Hungary ever since.The principal beneficiaries were the Kingdom of Romania, the Czechoslovak Republic, the Kingdom of Serbs, Croats and Slovenes (later Yugoslavia), and the First Austrian Republic. One of the main elements of the treaty was the doctrine of "self-determination of peoples", and it was an attempt to give the non-Hungarians their own national states. In addition, Hungary had to pay war reparations to its neighbours. The treaty was dictated by the Allies rather than negotiated, and the Hungarians had no option but to accept its terms. The Hungarian delegation signed the treaty under protest, and agitation for its revision began immediately.The current boundaries of Hungary are the same as those defined by the Treaty of Trianon, with some minor modifications until 1924 regarding the Hungarian-Austrian border and the notable exception of three villages that were transferred to Czechoslovakia in 1947.After World War I, in 1921, only one plebiscite (later known as the Sopron plebiscite) was allowed concerning disputed borders on the former territory of the Kingdom of Hungary. It settled a small dispute between Austria and Hungary. During the Sopron-area plebiscite, the polling stations were supervised by army officers of the Allied powers.