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.
Military history of the Russian Empire
More serious was the Bulavin Rebellion in 1707. Opposed to the government position regarding fugitives and influenced by anti foreignism, Konrad Bulavin, a leader of the Don Cossacks, started a rebellion. This was not the first uprising in the enstrangled relations between Russia and the cossacks, but it followed the same pattern; the rebellion spread across the south widely, and at its climax may have involved as many as 100,000 men, but was ill-organized and badly led. The rebellion was systematically suppressed by Russian troops pulled off the front; dissension spread among Bulavin's men, and he committed suicide in July 1708. The remainder of the rebellion was mopped up by 1709.
Regardless, by the summer of 1708, Charles was positioned in Lithuania, facing a road directly towards Moscow. However, he faced a desolate tundra, deliberately laid bare by Russian forces and protected by the significant fortress of Smolensk. His troops were constantly being harassed by Russian light troops, and reinforcements were still en route. Diplomatically, although Peter offered deals that would return all of the land he captured, save Saint Peterburg and Neva, Charles would not settle for anything less than Swedish victory. Ukraine, fertile and as yet untouched by the war, lay to the south; he also knew that Cossack hetman Ivan Mazepa, who largely controlled Ukraine under Peter, was secretly scheming against his tsar. Thus, the Swedes turned south, and entered Ukraine instead.