Beginning (January–April 1648) On January 25, 1648, Khmelnytsky brought a contingent of 400–500 Cossacks to the island of
Tomakivka, 60 kilometres to the south of
Khortytsia, and attacked the
Sich on
Mykytyn Rih, which had been guarded by
Crown Army troops and
Registered Cossacks. The Following the defeat of the royal garrison, Registered Cossacks joined the rebels, and their commander fled. Once at the Sich, his oratory and diplomatic skills struck a nerve with oppressed Cossacks. As his men repelled an attempt by Commonwealth forces to retake the Sich, more recruits joined his cause. The
Cossack Rada elected Khemlnytsky
Hetman by the end of the month. Khmelnytsky threw most of his resources into recruiting more fighters. He sent emissaries to
Crimea, enjoining the
Tatars to join him in a potential assault against their shared enemy, the Commonwealth. By April 1648 word of an uprising had spread throughout the Commonwealth, as Khmelnytskyi's
universals calling for the defence of "
ancient Greek faith" against "Polish enemies" were distributed around Ukraine. The hetman also used his connections to acquire
gunpowder and other military goods in
Volhynia,
Galicia and even in Poland itself. After diplomatic negotiations with
Crimean khan Islam III Giray, a military alliance was created between him and the Cossacks. Simultaneously, Khmelnytsky engaged in written correspondence with Crown hetman
Mikołaj Potocki, urging him to abolish the Ordination of 1638, remove crown troops from Ukraine and allow the Cossacks to engage in naval campaigns. These demands were likely part of a tactic aimed to prolong the time for military preparations, and were discarded by authorities.
Initial Cossack victories (April–May 1648) Either because they underestimated the size of the uprising, or because they wanted to act quickly to prevent it from spreading, the Commonwealth's Grand Crown Hetman Mikołaj Potocki and Field Crown Hetman
Marcin Kalinowski sent 3,000 soldiers under the command of Potocki's son,
Stefan, towards Khmelnytsky, without waiting to gather additional forces from
Prince Jeremi Wiśniowiecki. Four regiments of Registered Cossacks were sent on boats down by the
Dnieper, meanwhile two others joined a
mercenary squad marching from
Kryliv. After leaving the Sich in late April, the Cossack army, numbering around 8,000 men, joined forces with a 3,000-4,000 squad of
Perekop bey Tugay. with
Tugay Bey'' by
Juliusz Kossak. After the victory at Zhovti Vody, Khmelnytsky's vistorious Cossacks swiftly marched northwards, approaching the camp of both crown hetmans on the bank of
Ros river near
Korsun. On 25 May the troops of colonel
Maksym Kryvonis, aided by Tatars of Tugay Bey, cut the ways of retreat for Polish forces. During an
breakout attempt, the troops of the elder Potocki and Kalinowski were ambushed in a deep
ravine on the road leading from Korsun to
Bohuslav. Despite fighting bravely, both commanders were captured and imprisoned by the Tatars, and most of their soldiers perished. In addition to the loss of significant forces and military leadership, the Polish state also lost King
Władysław IV Vasa, who died in 1648, a few days before the Battle of Korsun, leaving the Crown of Poland leaderless and in disarray at a time of rebellion. The szlachta was on the run from its peasants, their palaces and estates in flames. All the while, Khmelnytsky's army marched westward.
First attempts at diplomacy (Summer 1648) Following the king's death, the real power over the Commonwealth became concentrated in the hands of
chancellor Jerzy Ossoliński. At his initiative, in June a government delegation was sent to the rebels, headed by Orthodox nobleman
Adam Kysil. Khmelnytsky's campaign in Galicia served as a demonstration of his army's force. After reaching
Lviv in early October, the Cossack army besieged the city for three weeks before lifting the siege in exchange for a ransom of 200,000
ducats, with much of the sum being used to pay the hetman's Tatar allies. After obtaining the ransom, on 26 October the Cossack army moved to besiege
Zamość. Simultaneously, a peasant war continued to burn in the Cossacks' rear, bringing devastation to noble estates in Volhynia, Galicia and
Pokuttia and resulting in deaths of many members of the
szlachta. Possible capture of Zamość by Khmelnytsky would make the rebels' way on
Warsaw practically open, so a possibility of calling up a
pospolite ruszenie was viewed by the Sejm, with
Jeremi Wisniowiecki being appointed to lead it. In the simultaneous electoral fight between various candidates for the Polish throne, Khmelnytsky hinted at his support for
John II Casimir Vasa. At the same time, the size of the Cossack army was decreasing due to exhaustion, hunger, disease and loss of motivation among many rebels. After the election of John II Casimir as Polish king on 17 November, parts of the
Cossack starshyna voiced their support for negotiations with the new monarch.
New ceasefire and Khmelnytsky's claims (Winter of 1648-1649) 's envoy by Khmelnitsky in
Zamość. According to Hrushevsky, John Casimir personally sent Khmelnytsky a letter informing the Cossack leader about his election. He assured him that he would grant Cossacks and all followers of the Orthodox faith various privileges and requested for Khmelnytsky to stop his campaign and await the royal delegation. Khmelnytsky answered that he would comply with his monarch's request and then turned back. On 23–24 November Cossack troops left Zamość. On his march back to Ukraine, Khmelnytsky issued orders for revolting peasants to obey their landlords. On 2 January 1649, Khmelnytsky triumphantly entered
Kyiv, where he was met by
Patriarch Paisius of
Jerusalem and
Kyiv Metropolitan Sylvester Kosiv and publicly hailed as "the Moses, savior, redeemer, and liberator of the people from Polish captivity... the illustrious ruler of Rus". It became clear to the Polish envoys that Khmelnytsky had positioned himself no longer as simply a leader of the Zaporozhian Cossacks but as that of an independent state and stated his claims to the heritage of the
Rus'. A
Vilnius panegyric in Khmelnytsky's honour (1650–1651) explained it: "While in Poland it is King Jan II Casimir Vasa, in Rus it is Hetman Bohdan Khmelnytsky".
Campaign of 1649 The ceasefire reached at Zamość was hard to support for both sides, and already in March 1649 Khmelnytsky sent a number of his units to fortify the defence on
Sluch and
Murafa rivers, meanwhile
magnate forces crossed the
Horyn. From February, hostilities were taking place around
Bar in Podolia. Tatar forces were gathering in Ukraine, with
khan Islam III Giray personally arriving to lead his troops. By late May, 120-150 thousand men, including 30-40 thousand Cossacks, as well as numerous recruits and volunteers, had gathered in the vicinity of Kyiv. From there, the force marched to meet the Polish crown army, which counted only up to 15,000 soldiers. Upon Khmelnytsky's approach to
Starokostiantyniv in late June, Polish troops commanded by
Adam Firlej retreated to the
fortress of Zbarazh. After failing to capture the fortification, on 20 July Cossack troops started a
siege. Amidst the siege, in early August elements of Cossack and Tatar cavalry jointly led by Khmelnytsky and Islam III Giray moved out to meet the Polish relief force advancing from Zamość, which numbered 15-20 thousand soldiers and was personally led by the king. On 15 August, the royal army was ambushed by Khmelnytsky's troops while crossing the
Strypa river near the town of
Zboriv. In the following
battle the crown army lost up to 7,000 men, and the monarch himself found himself surrounded by the Cossacks and Tatars. In order to break the alliance between Khmelnytsky and the khan, John II Casimir sent envoys to the Tatar camp. As a result of following negotiations, which were later joined by the Cossacks as well, on 19 August 1649 the hetman agreed to the
Treaty of Zboriv, according to which the Commonwealth would make numerous concessions. The treaty provided autonomy to Cossack-held voivodeships of
Kyiv,
Bratslav and
Chernihiv, as well as eastern parts of Volhynia and Podolia up to the river Sluch. Administrative positions in those areas could be held only by Orthodox
Ruthenian nobility, and all
Jesuits and
Jews had to be expelled. Participants of the rebellion were to get
amnesty. Following the Treaty of Zboriv, on 23 August Cossack troops lifted the siege of Zbarazh, ending the campaign. The return of peace was marred by the actions of Tatars, who, on their way back to
Crimea, engaged in the taking of numerous captives from among the local population, violating the agreements with Cossacks. The peace treaty itself turned to be short-lived, and by 1650 the pro-war party took head in the Commonwealth's politics, starting preparations for new hostilities.
Campaign of 1651 In December 1650, the Sejm approved the decision to increase the size of the Polish and Lithuanian armies to 36 and 15 thousand men respectively, and to introduce general mobilization of szlachta (
pospolite ruszenie) for the next year. By April 1651, the mobilized forces, numbering 40,000 regular soldiers, as many mercenaries and up to 60-80 thousand members of noble militia, had been concentrated near
Sokal on the border of Galicia and Volhynia. Khmelnytsky meanwhile concentrated his troops, numbering up to 100,000 men, around half of them Cossacks, near Zbarazh. There the hetman's forces were joined by Tatar cavalry of Islam III Giray, numbering 30-40 thousand horsemen. On 28 June 1651 the two opposing armies met in a lowland on the outskirts of the town of
Berestechko, starting what would become
one of the largest and bloodiest European battles of the 17th century. After two days without a decisive winner, the morning of 30 June saw a lull in fighting due to thick
fog covering the battlefield. After midnight, Commonwealth cavalrymen led by Jeremi Wisniowiecki performed an attack, which allowed
German mercenaries to break through Cossack positions and reach Islam Geray's tent. The attack, during which the ruler himself was wounded and his deputy killed, made the Tatars flee in panic. Attempting to stop his essential allies from leaving the battlefield, Khmelnytsky pursued the retreating khan, but was taken prisoner by his men. Having lost the support of Tatars and deprived of their commander, the Cossacks retreated to the banks of river Pliashivka, where they erected a temporary fortification, defending it for the following ten days. Finally, on the night of 9 to 10 June Cossack forces under the leadership of Khmelnytsky's deputy
Ivan Bohun started a retreat across the river. However, the withdrawal of Cossack cavalry caused panic among mobilized peasants, leading to the destruction of Bohun's
rearguard. During one day, over 8,000 soldiers of the Cossack army perished, with Polish troops capturing most of their opponents' artillery and gunpowder and taking control over Khmelnytsky's documents,
regalia and the hetman's treasury. Bohun was able to retreat with a cavalry corps numering 20,000 men, as well as parts of artillery. Berestechko didn't lead to a decisive defeat for Cossacks and their army fully recovered two months after the battle, but nonetheless Polish magnates recovered their possessions in
Right-Bank Ukraine, with the Right-Bank population fleeing to
Left-Bank and
Sloboda Ukraine. According to Ukrainian historian
Natalia Yakovenko, the battle represented a turning point, during which the uprising led by Khmelnytsky transformed from a
civil war inside of the Commonwealth into a full-scale Polish-Ukrainian war. In their pursuit of the retreating Cossack troops, Commonwealth forces were incessantly harassed by
partisans, with local peasants ruining bridges and river crossings. Hunger forced the soldiers to feed themselves with dead horses and grain from the fields, and epidemics contributed to mass deaths and desertion of troops. Jeremi Wisniowiecki himself died during the march after falling sick near
Pavoloch. Meanwhile, Khmelnytsky was able to escape Tatar captivity and arrived to
Bila Tserkva, where he gathered troops from around Right-bank Ukraine, establishing a fortified camp. By the second half of August, the hetman could amass an army of 25,000 Cossacks and 6,000
Nogays. Another 4,000 Cossacks were stationed in Left-bank Ukraine threatening Kyiv, which had been recently taken by the Lithuanian army of
Janusz Radziwiłł. After both sides had been exhausted at
Bila Tserkva, they signed
Treaty of Bila Tserkva, which was less favourable for Cossacks. According to its terms, the Cossack registry was limited to 20,000, and Cossack autonomy was limited to Kyiv Voivodeship only. The hetman obliged himself to abandon the treaty with Crimean Tatars and refrain from any foreign contacts. However, the peace treaty was never ratified, as voting at the new Sejm, which gathered in early 1652, was blocked by one of the deputies executing his right of
liberum veto.
Campaigns of 1652-1653 The failure to ratify the Treaty of Bila Tserkva allowed Khmelnytsky to resume hostilities, and in April 1652 he informed his starshyna about new war preparations. The formal ground for a new campaign was the
planned invasion of a Cossack-Tatar force led by the hetman's son
Tymish into
Moldova. Troops led by field hetman
Marcin Kalinowski, counting 12,000
hussars and 8,000 infantry, marched to stop the Cossack force and encamped themselves near the Batih, a mountain located over the
Buh river not far from
Ladyzhyn. The Polish force was taken by surprise when Tatar cavalry attacked the camp, surrounding it by the evening of 1 June. Next day Polish positions were stormed and taken by force, killing Kalinowski and half of his hussars. The
Battle of Batih served as a revenge for the previous year's defeat at Berestechko, with Khmelnytsky ordering Cossacks to kill all Polish prisoners, part of whom were bought from the Tatars, in an event known as the
Batih massacre. Following the victory at Batih, Khmelnytsky proposed the Commonwealth to restore the Treaty of Zboriv, but the Sejm refused the offer. By the end of the year, Commonwealth army was expanded to 34,000 soldiers, including 68 new cavalry units. In March 1653 a new invasion by Polish troops started in the area of
Bratslav, with units commanded by
Stefan Czarniecki devastating the region. In July of the same year the king personally arrived to
Hlyniany near Lviv in order to head the crown army. All approaches for new negotiations by Khmelnytsky were demonstratively ignored. In early October, the royal army established its camp near
Zhvanets on the
Dniester, across the river from
Khotyn. Numbering around 40,000 soldiers, the Polish force was blocked by a similar-sized army of Cossacks supported by Tatars. After an exhausting
siege, khan Islam III Giray initiated a round of negotiations, which resulted in the signing of a new peace treaty on 17 December.
Muscovy's entry into the conflict (1654-1655) As the siege of Zhvanets was still ongoing, on 11 October 1653 the
Zemsky Sobor of
Muscovy approved the decision to accept the Zaporozhian Host under the rule of the tsar. This signified a new escalation in the war, which after six years started to attain an international character. Following the signing of the
Treaty of Pereyaslav in early 1654, a 18,000-strong Cossack force commanded by
acting hetman Ivan Zolotarenko assisted the tsar's army during its invasion of Belarus. By July 1654 Zolotarenko's troops had occupied the areas of
Bykhaw,
Krychaw and
Mogilev, where they spent the following winter. During the summer of 1655 Cossack troops continued their advance northwards, taking
Svislach and
Minsk. After uniting with Muscovite forces, Zolotarenko's troops moved on to Vilnius and
Grodno. Facing the newly established alliance between the Cossacks and Moscow, in June 1654 Poland signed an "eternal treaty" with Crimea in
Bakhchisaray, breaking the union between the khan and Khmelnytsky. From that point, royal troops and Tatars would coordinate their actions against the hetman. In October 1654 a 30,000-strong force under command of Seweryn Potocki entered the region of Bratslav, meanwhile the Tatars moved in the direction of Uman. The raid devastated the region of Podolia, forcing thousands to flee to Moldova and delaying Khmelnytsky's offensive in the direction of Volhynia. In late January 1655 the hetman's troops were finally able to unite with Moscow's troops commanded by
voivode Vasily Sheremetev. Amid severe frost, on 29–31 January the allied armies encountered the crown army at the
Battle of Okhmativ. The action ended in a stalemate, but succeeded in stopping the Polish advance. Khmelnytsky's passivity during the siege of Lviv was influenced by his opposition to claims issued by Charles X on
Galicia, as the hetman planned to attach that territory to his state. In addition, Muscovite voivodes provoked the Cossacks by demanding that all cities taken by Khmelnytsky's troops pledge allegiance to the tsar. A similar situation arose in the Cossack-occupied areas of southern Belarus, where the rule of hetman's administration was put in question by Moscow's representatives, who considered that territory to be the property of their monarch. In May 1656 the tsar's government, fearing the rise of Sweden, broke all relations with Charles X and started
peace negotiations with the Commonwealth. The talks began on 22 August in Vilnius, but the delegation of Cossack representatives sent by Khmelnytsky was denied access to the meeting. Furious at this show of disrespect, the hetman started looking for ways to break the alliance with Moscow. In autumn 1656 Khmelnytsky signed a
series of agreements with Sweden, Transylvania,
Wallachia,
Austria, Moldova and Crimea, and renewed talks with Poland and
Turkey. Simultaneously, a Cossack corps numbering 20,000 soldiers under command of Antin Zhdanovych joined the forces of George II Rakoczi and Swedish king in
their campaign against Poland. Suffering from ill health, in April Khmelnytsky gathered a council of Cossack officials and declared his 16-year-old son
Yuri to be his successor. After suffering a
stroke, on 6 August 1657 Bohdan Khmelnytsky died in Chyhyryn, leaving Ukraine surrounded by numerous enemies. ==Other theatres==