Brusilov offensive

The Brusilov offensive (Russian: Брусиловский прорыв Brusilovskiĭ proryv, literally: "Brusilov's breakthrough"), also known as the "June advance", of June to September 1916 was the Russian Empire's greatest feat of arms during World War I, and among the most lethal offensives in world history. The historian Graydon Tunstall called the Brusilov offensive the worst crisis of World War I for Austria-Hungary and the Triple Entente's greatest victory, but it came at a tremendous loss of life. The heavy casualties eliminated the offensive power of the Imperial Russian Army and contributed to Russia's revolution the next year.

The offensive involved a major Russian attack against the armies of the Central Powers on the Eastern Front. Launched on 4 June 1916, it lasted until late September. It took place in eastern Galicia (present-day northwestern Ukraine), in the Lviv and Volyn Oblasts. The offensive is named after the commander in charge of the Southwestern Front of the Imperial Russian Army, General Aleksei Brusilov. The largest and most lethal offensive of the war, the effects of the Brusilov offensive were far-reaching. It relieved German pressure on French forces at Verdun, and helped to relieve the Austro-Hungarian pressure on the Italians. It inflicted irreparable losses on the Austro-Hungarian Army, and induced Romania to finally enter the war on the side of the Entente. The human and material losses on the Russian side also greatly contributed to the onset of the Russian Revolution the following year.