Answer
Yemelyan Pugachev was a leader of a major popular uprising in the Russian Empire, which lasted from 1773 to 1775. He was a Cossack and claimed to be Peter III, the deposed emperor of Russia. The rebellion started in the Volga region and spread to the Urals and Siberia. The rebels captured several cities and proclaimed a new government. The uprising was eventually suppressed by the Russian army.