On 28 June 1914 Austro-Hungarian Archduke Franz Ferdinand is assassinated in Sarajevo, the capital of Bosnia-Herzegovina.
In its ensuing dispute with Serbia, Austria-Hungary refuses to be placated. Germany sides with Austria-Hungary when the situation deteriorates. On 3 August 1914 Germany declares war on France. Britain in turn declares war on Germany on 14 August. The First World War has begun.
After four years of exhausting and bloody conflict, the war ends on 11 November with the signing of a general armistice. Germany has accepted a humiliating defeat. The German king has been forced to abdicate and the Austro-Hungarian Empire has been destroyed.
Hungary proclaims its independence, but in the post-war reparations settlement loses more than two-thirds of its territory. Transylvania is ceded to Romania. Croatia, Slavonia and Vojvodina go to Yugoslavia. Slovakia becomes part of Czechoslovakia. In 1919 communists seize control of the government and announce the establishment of the Hungarian Soviet Republic.
Communist rule does not last the year. When their promise to restore the country's borders backfires badly, the communists are ousted by a military junta. A campaign of "white terror" by the new regime targets communists, socialists, Jews and leftist intellectuals. About 5,000 are executed and 75,000 jailed. Nearly 100,000 flee into exile. Hungarian Jews suffer particularly badly.
In 1910 Hungarian Jews number around 900,000, or about 5% of the population. They make up the bulk of the country's middle class and dominate the finance and business sectors of the economy. By 1945 only about 120,000 Jews remain.