Pugachev's Rebellion
Pugachev's Rebellion (Peasants' War 1773-75, Cossack Rebellion) of 1773-75 was the principal revolt in a series of popular rebellions that took place in the Russian Empire 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 Imperial Russian Army, against a background of profound peasant unrest and war with the Ottoman Empire. After 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.
Volga Cossacks
The Volga Cossacks participated in Yermak's conquest of Siberia. Due to the creation of the Tsaritsyn fortified line in the 18th century, the central government decided to form the Volga Cossack Host (Волгское казачье войско) consisting of 1057 families (mostly Don Cossacks) with the center in Dubovka (north of Tsaritsyn). The Volga Cossacks participated in the Pugachev Rebellion in 1773-1775.