In January 1648, a major anti-Polish
uprising led by
Bohdan Khmelnytsky began in the
Zaporizhia lands. Supported by popular masses and by
Crimean Khanate the rebels won a number of victories over the government forces of the
Polish–Lithuanian Commonwealth seeking the increase of Cossack registry (kept at the expense of the state treasury), weakening of the Polish aristocratic oppression, oppression by the Jews who governed estates as well as recovery of positions of the Orthodox Church in own lands. However, the autonomy obtained by Khmelnytsky found itself squeezed between three Great powers: the
Polish–Lithuanian Commonwealth, the
Tsardom of Russia and the
Ottoman Empire. Being the main leader of the uprising,
Bohdan Khmelnytskyi was not able to declare independence because he was not a legitimate monarch, and there was not such a candidate among other leaders of the uprising. Considering the economic and human resources, the rebellion was taking place in regions of the Polish Crown, Kijów (
Kyiv), Czernihow (
Chernihiv) and Bracław (
Bratslav) voivodeships. The Crimean Khan, the only ally, was not interested in a decisive victory of Cossacks.
Cossack — Moscow negotiations timeline It is believed that negotiations to unite the Zaporizhian lands with Russia started as early as in 1648. Such idea is common among Soviet historians of Ukraine and Russia such as
Mykola Petrovsky. Many other Ukrainian historians among which are
Ivan Krypiakevych,
Dmitriy Ilovaisky,
Myron Korduba, Valeriy Smoliy and others interpret negotiations as an attempt to attract the tsar to military support of Cossacks and motivate him to struggle for the Polish Crown which became available after the death of
Władysław IV Vasa. • June 18, 1648 – the first known official letter of
Bohdan Khmelnytskyi to Tsar
Alexis I; it was finished: "So let the God fulfill the prophecy, which was celebrated from ancient times, to which we gave ourselves, and to the merciful feet of your royal majesty, like the lower ones, submit obediently." • June 18, 1648 – letter of Khmelnytskyi to the Muscovite voivode of Siveria, Leontiev. Mention of favorable attitude of the Cossacks to the tsar. The issue of allegiance to the tsar is not raised. • July 21, 1648 – letter of Khmelnytskyi to the Muscovite voivode of Putivl, Pleshcheyev. Mention of motivation of the Russian tsar to the struggle for the Polish Crown. The issue of allegiance to the tsar is not raised. • January 1649 – in Moscow, Patriarch Paisius convinced the tsar of Khmelnytskyi's intentions "...striking with forehead to your Imperial Majesty, so the emperor ordered to grant him, Khmelnytskyi and all the Zaporizhian Host adoption under His high imperial hand...", but in the Muzhylovsky's notes is mentioned only request for military assistance, while the issue of allegiance to the Tsar was not raised. to encourage him to fight for the Polish Crown. • March 1, 1651 –
Zemsky Sobor in
Moscow. The Moscow clergy found it possible in case of not following by the Polish side conditions of the Eternal Peace permit Alexis Mikhailovich to adopt the
Zaporizhian Host as one of his subjects. • September 1651 – Osman-aga, an Ottoman envoy, arrived to
Chyhyryn, and informed about readiness of the
High Porte to take Ukraine under its protection. Khmelnytskyi did not rush anticipating the Moscow's answer. • March 1652 – Khmelnytskyi's envoys in Moscow. Envoy
Ivan Iskra proposed immediately to take the
Zaporizhian Host under the tsar's custody. The tsar's government agreed to take only the army without the territory anticipating in the future give it lands in the interfluve of
Don and Medveditsa. ==Preparations for official meeting==