The international event marked by the signing of the Treaty of Trianon in 1920 was the aftermath of World War I. The treaty was signed on June 4, 1920, between the Allied Powers and Hungary, a former part of the Austro-Hungarian Empire. The treaty resulted in significant territorial losses for Hungary, reducing its size and population dramatically. In addition to altering borders, Trianon imposed military restrictions and economic reparations, leading to lasting grievances within Hungary. The treaty's consequences fueled nationalist sentiments and contributed to regional tensions in Central Europe, influencing the interwar period.