The Pereiaslav Agreement or Pereyaslav AgreementPereyaslav Agreement Britannica. (, ) was an official meeting that convened for a ceremonial pledge of allegiance by Zaporozhian Cossacks to Russian tsar Alexis () in the town of Pereiaslav in central Ukraine, in January 1654. The ceremony took place concurrently with ongoing negotiations that started on the initiative of Hetman Bohdan Khmelnytsky to address the issue of the Cossack Hetmanate with the ongoing Khmelnytsky Uprising against the Polish–Lithuanian Commonwealth and which concluded the Treaty of Pereiaslav (also known as the March Articles). The treaty itself was finalized in Moscow in April 1654 (in March according to the Julian calendar).

Khmelnytsky secured the military protection of the Tsardom of Russia in exchange for allegiance to the tsar. An oath of allegiance to the Russian monarch from the leadership of the Cossack Hetmanate was taken, shortly thereafter followed by other officials, the clergy and the inhabitants of the Hetmanate swearing allegiance. The exact nature of the relationship stipulated by the agreement between the Hetmanate and Russia is a matter of scholarly controversy. The council of Pereiaslav was followed by an exchange of official documents: the March Articles (from the Cossack Hetmanate) and the tsar's declaration (from Russia).

The council was attended by a delegation from Moscow headed by Vasiliy Buturlin. The event was soon thereafter followed by the adoption in Moscow of the so-called that stipulated an autonomous status of the Hetmanate within the Russian state. The agreement precipitated the Russo-Polish War of 1654–1667. The definitive legal settlement was effected under the Treaty of Perpetual Peace in 1686 concluded by Russia and Poland that re-affirmed Russia's sovereignty over the lands of Zaporozhian Sich and left-bank Ukraine, as well as the city of Kiev.

Background of negotiations 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.Petrovsky, M. Liberation war of the Ukrainian people against the oppression of szlachta Poland and annexation of Ukraine to Russia (1648-1654). Kiev, 1940. Many other Ukrainian historians among which are Ivan Krypiakevych,Krypiakevych, I. Bohdan Khmelnytskyi. Lviv, 1990. Dmitriy Ilovaisky,Ilovaisky, D. History of Russia. Vol.5. Moscow, 1905. Myron Korduba,Korduba, M. Struggle for the Polish Crown after the death of Władysław IV. Sources to the History of Ukraine-Ruthenia. Vol.12. Lviv, 1911 Valeriy SmoliySmoliy, V., Stepankov, V. Bohdan Khmelnytskyi. Social-political portrait. Kiev, 1995. 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.Acts relating to the history of Southern and Western Russia Collection and publications of the Archaeographical Commission. Vol.3. Saint Petersburg, 1861. 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. end of December 1648 – departing of Khmelnytskyi delegation to Moscow. The delegation included the chief envoy Syluyan Muzhylovsky and Patriarch Paisius I of Jerusalem.Horobets, V. Moscow policy of Bohdan Khmelnytskyi: objectives and attempts of their realization. Ukraine and Russia in historical retrospective: outlines in three volumes. Vol.1. Institute of History of Ukraine (National Academy of Sciences of Ukraine). Kiev "Naukova Dumka", 2004. 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...",Unification of Ukraine with Russia. Documents and materials in three volumes. Vol.2. Moscow 1954. but in the Muzhylovsky's notes is mentioned only request for military assistance, while the issue of allegiance to the Tsar was not raised. April 1649 – meeting of Khmelnytskyi with the tsar's envoy Grigoriy Unkovsky in Chyhyryn. Hetman emphasized on the kinship of Ukraine with Moscow: "...from the baptizing by St.Vladimir we had with Moscow our one pious Christian faith and one power..." and asked for military assistance. May 1649 – deportation of Khmelnytskyi's envoys to Moscow headed by Chyhyryn Colonel Fedir Veshnyak. In accreditation letter it was expressed petition for protectorate of the Russian tsar. "...take under own mercy and defense... whole Ruthenia" At the same time, similar delegation was sent to the Prince of Transylvania George II RákócziKorduba, M. Between Zamość and Zboriv. "Shevchenko Scientific Society notes". Vol.33. Lviv 1922. to encourage him to fight for the Polish Crown. August 16, 1649 – hollow victory at the Battle of Zboriv. Betrayed by Crimean Tatars, Bohdan Khmelnytskyi blamed Moscow for not sending help. Cossack-Moscow relations worsened. Hetman and his associates resorted to diplomatic pressure on Moscow: openly expressed about the need for campaign onto the Muscovites, and refused to give impostor Timofey Akudinov who claimed to be the son of Moscow Tsar Vasili IV of Russia. March 1650 – Khmelnytskyi ignored orders of the king of Poland on preparations to a shared Polish-Crimean campaign against Moscow. Summer-fall of 1650 – revival of the Turkish-Ukrainian dialogue to transfer under the Ottoman protectorate: "... Ukraine, White Ruthenia, Volhynia, Podolie with whole Ruthenia all the way to Wisla..."Bohdan Khmelnytskyi documents (1648-1658). Compiled by I.Krypiakevych, I.Butych. Kiev, 1961.Butych, I. Two unknown letters of Bohdan Khmelnytskyi. Shevchenko Scientific Society notes. Vol.222. Lviv, 1991. 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 On October 1, 1653, the Zemsky Sobor that took place in Moscow in the fall adopted the decision on including Ukraine to the Russian state, and on November 2, 1653, the Moscow government declared war on the Polish–Lithuanian Commonwealth. To conduct negotiations between two states, a large delegation headed by the boyar Vasili Buturlin departed from Moscow to Ukraine. In its composition were also okolnichiy I. Olferiev, dyak L. Lopukhin and representatives of the clergy.

The travel took almost three months. Besides bad roads and disorder, a new royal standard had to be made, the Buturlin's speech text, and the mace (bulawa) designated to Hetman disappeared several precious stones that had to be recovered. Also, the delegation had to wait almost a week for arrival of Bohdan Khmelnytskyi, who was delayed in Chyhyryn at the burial of his older son Tymofiy Khmelnytsky and later was not able to cross the Dnieper since the ice on the river was not strong enough.

Pereiaslav meeting and the autonomous Cossack state

At a meeting between the council of Zaporozhian Cossacks and Vasiliy Buturlin, representative of Tsar Alexis I of Russia, during the Khmelnytsky Uprising. The Pereiaslav Council of Ukrainians took place on January 18; it was meant to act as the supreme Cossack council and demonstrate the unity and determination of the "Rus' nation". Military leaders and representatives of regiments, nobles and townspeople listened to the speech by the Cossack hetman Bohdan Khmelnytsky, who expounded the necessity of seeking the Russian protection. The audience responded with applause and consent. The treaty, initiated with Buturlin later on the same day, invoked only protection of the Cossack state by the tsar and was intended as an act of official separation of Ukraine from the Polish–Lithuanian Commonwealth (Ukrainian independence had been informally declared earlier in the course of the Uprising by Khmelnytsky). Participants in the preparation of the treaty at Pereiaslav included, besides Khmelnytsky, Chief Scribe Ivan Vyhovsky and numerous other Cossack elders, as well as a large visiting contingent from Russia.