Ivan Vyhovsky, serving in the Polish military, had been captured by Khmelnystsky's rebel Cossack forces at Zhovti Vody in May of 1648; freed on account of his education and experience, he had risen to become secretary-general or chancellor of the Cossacks and one of Khmelnytsky's closest advisors.

Elected hetman upon the death of Khmelnytsky, Vyhovsky seeks to find a counterbalance to the pervasive Russian influence present in Ukraine after the 1654 Treaty of Pereyaslav.

While the Cossack elite and the ecclesiastical authorities support this pro-Polish orientation, the masses and the Cossack rank-and-file remain deeply suspicious and resentful of the Poles, by whom they have long been forced into serfdom.

As a result, some Cossacks, led by Iakiv Barabash, put forward an alternative candidate for the hetmancy in Martyn Pushkar, the colonel of the Poltava regiment of Cossacks.

The rebellion against the hetman grows, and comes to a head when Vyhovsky's forces clash with the pro-Russian Cossacks in June of 1658.

Vyhovsky's forces prevail, killing Pushkar and forcing Barabash to flee (he will later be captured and executed).

However, it has clearly been a fratricidal conflict, resulting in some 50,000 deaths.

Vyhovsky, following his consolidation of power within Ukraine, attempts to reach an acceptable agreement with the Poles, whose position has been further weakened by a string of losses in the Russo-Polish War.

Encouraged by his aristocratic friend Iurii Nemyrych, Vyhovsky enters negotiations with the Polish government, which results in the Treaty of Hadiach of September 1658, signed by representatives of the Polish-Lithuanian Commonwealth (represented by S. Bieniewski and K. Jewłaszewski) and Cossacks (represented by Hetman Ivan Vyhovsky and starshyna, the elders), Yurii Nemyrych, the architect of the treaty, and Pavlo Teteria.

The treaty is designed to elevate the Cossacks and Ruthenians to the position equal to that of Poland and Lithuania in the Polish-Lithuanian Union and in fact transforming the Polish-Lithuanian Commonwealth into a Polish-Lithuanian-Ruthenian Commonwealth (Rzeczpospolita Trojga Narodów, "Commonwealth of Three Nations").

Under the conditions of the treaty, Ukraine is to become a third and autonomous component of the Polish-Lithuanian Commonwealth, under the ultimate sovereignty of the King of Poland, but with its own military, courts, and treasury.

Additionally, adherents of the Orthodox faith are to receive equal consideration as Catholics.

As such, the treaty as signed would have assured the Cossacks of autonomy and dignity to an extent they had not known for centuries.

Vyhovsky, in the southern theater, fails to wrest Kiev from Sheremetev's control.

The news of a Cossack-Polish alliance alarms Moscow and the Ukrainian Cossacks opposing Vyhovsky (led by Ivan Bezpalyi) to the extent that an expeditionary force is dispatched to Ukraine in the autumn of 1658 headed by Prince Grigory Romodanovsky.

The Russian army arrives at the Ukrainian border on January, 30, 1659 and stands forty days until the supreme military commander Prince Aleksey Trubetskoy opens negotiations with Vyhovsky, as the Russian commander has instructions to persuade the Cossacks to make peace.

Vyhovsky's rivals, the Cossack forces of commanders Bezpalyi, Voronko and the Zaporizhian Cossacks of Barabash, join the Russian troops.

After the negotiations fail, hostilities begin.

Moscow's military commander not only supports the election by Vyhovsky's opponents of a new rival hetman, but starts actively to occupy towns held by Vyhovsky's supporters.

The latter are mercilessly exterminated along with widespread abuse and robbery of the civilian population.

The situation having escalated this far, open hostilities follow.

Skirmishes and attacks occur in different towns and regions throughout the country.

A huge army—of one hundred thousand according to "The Chronicle of the Witness" or one hundred and fifty thousand men according to Russian historian Sergey Solovyov—is in the spring of 1659 dispatched to Ukraine to assist Romodanovsky.

According to Russian army documents the intervention troops counted twenty-four thousand six hundred men.

The Russian army, together with anti-Vyhovsky insurgents, defeats Vyhovsky's troops in the battle of Romny and ...

...the battle of Lokhvytsya.

Prince Trubetskoy now decides to finish off the small four thousand-man garrison of the Konotop castle held by Cossacks of the Nizhyn and Chernihiv Regiments headed by Hryhoriy Hulyanytsky, a colonel of Nizhyn, before proceeding in his pursuit of Vyhovsky.

Trubetskoy's hopes for quick resolution of the Konotop stand-off dim when Hulyanytsky and his Cossacks refused to betray hetman Vyhovsky and mount a fierce and protracted defense of Konotop.

According to a historian named Markevych, on April 21, 1659, after a morning prayer, Trubetskoy orders an all-out assault on the fortress's fortifications.

The city is shelled, a few incendiary bombs are dropped inside, and the army moves on to capture the city.

At one point Trubetskoy's troops break through the city walls, but are repelled by the fierce resistance of the Cossacks inside.

After the fiasco of the initial assault, Trubetskoy abandons his plans of a quick assault and proceeds to shell the city and to fill the moat with earth.

The Cossacks stubbornly hold on in spite of all the fire unleashed on the city: during the night the earth put to fill in the moat is used to strengthen the city walls, and the besieged even undertake several counterattacks on Trubetskoy's investing army.

These attacks force Trubetskoy to move his military camp ten kilometers away from the city and thereby split his forces between the main army at his HQ and the army besieging Konotop.

Another attack on April 29 is also repelled; the Russians lose close to four hundred men and suffer around three thousand wounded.

Hetman Vyhovsky supports the negotiations with the Commonwealth, especially after suppressing a revolt led by the colonel of Poltava, Martyn Pushkar, and has severed relations with Tsardom of Russia for its violations of the Treaty of Pereyaslav of 1654.

The Treaty of Hadiach is, however, viewed by many Cossacks as 'too little, too late', and they especially oppose the agreement to return land property to the szlachta.

The Commonwealth has become very unpopular with ordinary Cossacks after the 1648 revolt.

Rank-and-file Cossacks see Orthodox Moscow as their natural ally and do not care for alliance with the Commonwealth.

Furthermore, Hadiach is too much a deal that merely benefits the elite of the Cossacks—the "starshyna"—who want to be recognized as equal to the Polish nobility.

Thus, while some Cossacks, among them Vyhovsky, support the Commonwealth, many do not, and Cossack unrest continues in Ukraine.

The Treaty of Hadiach, despite considerable Roman Catholic Clergy opposition, is on May 22, 1659, approved by Polish king and parliament (Sejm) , but with an emended text.

The idea of a Ruthenian Duchy, a Commonwealth attempt to regain influence over the Ukrainian territories and growing influence of Muscovy over the Cossacks within the Commonwealth, is completely abandoned.