Russia entered World War I Austria-Hungary Serbia Triple Entente Brusilov Offensive Austro-Hungarian Army high casualties Russian Revolution Nicholas II forced to abdicate later executed Russian Civil War Provisional Government Russian Republic O.S. Russian Constituent Assembly All-Russian Central Executive Committee Imperial Russian Army Central Russian federal Nicholas I
In 1914, Russia entered World War I in response to Austria-Hungary's declaration of war on Russia's ally Serbia, and fought across multiple fronts while isolated from its Triple Entente allies. In 1916, the Brusilov Offensive of the Imperial Russian Army almost completely destroyed the Austro-Hungarian Army. However, the already-existing public distrust of the regime was deepened by the rising costs of war, high casualties, and rumors of corruption and treason. All this formed the climate for the Russian Revolution of 1917, carried out in two major acts. In early 1917, Nicholas II was forced to abdicate; he and his family were imprisoned and later executed during the Russian Civil War. The monarchy was replaced by a shaky coalition of political parties that declared itself the Provisional Government, and proclaimed the Russian Republic. On 19 January [O.S. 6 January], 1918, the Russian Constituent Assembly declared Russia a democratic federal republic (thus ratifying the Provisional Government's decision). The next day the Constituent Assembly was dissolved by the All-Russian Central Executive Committee.
