Yemelyan Pugachev
Yemelyan Ivanovich Pugachev () (c. 1742 – ) was a Russian Cossack who led a great popular insurrection during the reign of Catherine the Great, claiming to be her late husband, Emperor Peter III. Alexander Pushkin wrote a notable history of the rebellion, "The History of Pugachev", and he recounted some of the events in his novel "The Captain's Daughter" (1836).
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.