Hungary as part of the dual monarchy of the Austro-Hungarian Empire, allied to Germany and Turkey against Britain, France and Russia, and from 1915, Italy.
The defeat in 1918 broke up the Austro-Hungarian Empire. Hungary became a republic. Its borders were significantly reduced under Treaty of Trianon in 1920, instantly casting millions of Hungarians outside of their national borders.
According to Dr Rétvári, “If Hungary had been able to manage its foreign and military affairs individually back in 1914, the country would have had “different borders and a different history in the 20th century.”