Pugachev's Rebellion (or the
Cossack Rebellion) of 1773-75 was the principal revolt in a series of popular rebellions that took place in Russia after
Catherine II seized power in 1762. It began as an organized insurrection of
Yaik Cossacks headed by
Yemelyan Pugachev, a disaffected ex-lieutenant of the
Russian Imperial army, against a background of profound peasant unrest and war with the
Ottoman Empire. After the initial success, Pugachev assumed leadership of an alternative government in the name of the assassinated Tsar
Peter III and proclaimed an end to
serfdom. This organized leadership presented a challenge to the imperial administration of
Catherine II.