qnli question: Who was in charge of the Russian Caucasus Army of Imperial forces? sentence: Although the Russian Caucasus Army of Imperial forces commanded by Nikolai Yudenich and Armenians in volunteer units and Armenian militia led by Andranik Ozanian and Tovmas Nazarbekian succeeded in gaining most of Ottoman Armenia during World War I, their gains were lost with the Bolshevik Revolution of 1917.[citation needed]