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.
Muhannad (jihadist)
On 1 August 2010, the rebel website Kavkaz Center posted an announcement from Dokka Umarov in which he stated he was stepping down from the top leadership position in the Caucasus Emirate and naming Aslambek Vadalov as his replacement. However, just three days later Umarov would retract his resignation, leading to confusion over who was actually in control of the North Caucasus insurgency. On 12 August, a video posted on a Russian militant website appeared featuring Muhannad, Khuseyn Gakayev, Vadalov, and Tarkhan Gaziev; in it, the four veteran field commanders alleged that Umarov's renunciation was disrespectful to his subordinates, and while they still pledged allegiance to the Caucasus Emirate, they no longer supported him. According to Muhannad, the primary reason for the mutiny was Umarov's disobedience of the mujahideen shura council's consensus that he step down; in response, Saifullah Gubdenski - leader of the Dagestani fighters - fiercely condemned Muhannad by accusing him and his foreign predecessors of "neglecting the aspirations of local rebel leaders" and lashing out at the "outsiders' selfish desire to install their men in leading positions in traditionally parochial" Caucasian militant groups. Furthermore, the vast majority of insurgents in the republics surrounding Chechnya continued to support Umarov, at one point reaching out for external theological support via the London-based Syrian Salafi ideologue named Abd al-Mun'im Mustafa Halima (also known as Abu Basir al-Tartusi), who called on Muhannad to "either repent and obey Emir Doku Abu Osman (Dokka Umarov) or leave the [North] Caucasus and return home." Umarov himself accused Muhannad of being the "main organizer of fitna (split/discord) among the Mujahideen" in Chechnya, 
and asked him to re-affirm his loyalty. When Muhannad did not, Umarov allegedly relieved him of his command, leading to a very significant break within militant ranks.