Ukrainian Lands in the XVI-XVII Centuries and the National-Liberation War

The Lublin Union and the Formation of the Polish-Lithuanian Commonwealth

The Union of Lublin, established in $1569$, marked a pivotal moment in Eastern European history, resulting in the unification of the Kingdom of Poland and the Grand Duchy of Lithuania into a single political entity known as the Rzeczpospolita (Polish-Lithuanian Commonwealth). The primary drivers for this union were the increasing attacks by Turks and Tatars, which threatened the security of the region, and Lithuania's significant defeats in ongoing wars. Additionally, there was a strategic push to spread Polish authority and civil administration across diverse lands.

The consequences of this union were complex and multifaceted. On the positive side, it facilitated the development of the economy and trade, led to the growth of new technologies, and unified Ukrainian lands within a single state structure. These lands also saw the expansion of Catholicism. However, the union brought negative social and cultural impacts, most notably the Polonization of the elite and the enserfment (zakripachennya) of the peasantry. Socio-economically, this era was defined by the "Filvarky" system—a form of manorial farming based on serf labor designed to produce grain for export. This kripotsnytska (serfdom) system was codified through the Lithuanian Statutes and the "Ustav na voloky," a significant land reform that structured agricultural production around fixed land allotments.

Religious Dynamics and the Rise of Orthodox Brotherhoods

During the late $16\text{th}$ century, religious identity became a central point of contention and social organization. Orthodox Brotherhoods (Pravoslavni Bratstva) emerged as powerful civic organizations to defend the interests of the Orthodox population. A prominent example was the Lviv Dormition (Uspenske) Brotherhood, which received stavropegic status in $1586$, meaning it was directly subordinate to the Patriarch rather than local bishops. In that same year ($1586$), the brotherhood opened its own school, which became a center for education and culture.

The religious landscape was further transformed in $1596$ by the Union of Brest (Beresteiska Tserkovna Uniya), which created the Greek Catholic Church. Led by figures like Ipatiy Potiy, this union sought to bring the Orthodox Church under the authority of the Pope while retaining Eastern rites. The consequences of this union included heightened social tension and the prolific development of polemical literature, which served as the primary medium for intellectual and religious debate between supporters and opponents of the union.

The Emergence and Structure of the Cossacks

The Cossacks emerged in the "Dyke Pole" (Wild Fields), a vast frontier territory. The primary reasons for the growth of this social group included the necessity of defending southern lands from Turkish and Tatar raids, the desire of various social classes to settle new, fertile territories, and the flight of peasants and townsfolk from the increasing oppression of enserfment. In $1556$, Dmytro Vyshnevetsky founded the first known Sich on the island of Mala Khortytsia, establishing a military center for the Zaporozhian Cossacks.

Cossack society was broadly divided into two groups: the Nyzovi (Lower) Cossacks, who resided in the Zaporozhian Sich, and the Reestrovi (Registered) Cossacks, who were in official service to the Polish state. The registration system began in $1572$ when King Sigismund II Augustus hired $300$ Cossacks. This was expanded in $1578$ by the Universal of Stephen Báthory, which increased the registry to $600$ men. The Registered Cossacks were recognized as a separate social class, granted Kleynody (military insignia), and given the town of Trakhtemyriv as their center.

Military Expeditions and Defense under Sahaidachny

The early $17\text{th}$ century was marked by significant Cossack military activity under the leadership of Hetman Petro Konashevych-Sahaidachny. In $1616$, he led a daring campaign against the fortress of Caffa (Kafa), donde they burned the fortress and liberated numerous prisoners. In $1618$, Sahaidachny led a Polish-Muscovite war effort that included a march on Moscow and culminated in the siege of the city. Perhaps his most famous contribution was in the Battle of Khotyn in $1620$ (alternatively dated $1621$), where a joint Polish-Cossack force successfully repelled a massive Turkish invasion, halting their expansion into Europe.

The Cossack Liberation Movement ($1591$-$1638$)

A series of uprisings against the Polish administration occurred between $1591$ and $1638$, driven by the desire to increase the Cossack registry, the oppression of the Orthodox faith, and the encroachment of the Polish nobility (szlachta) on Cossack rights. Early leaders included K. Kosynsky and S. Nalyvaiko, though their efforts were ultimately unsuccessful. In $1625$, M. Zhmailo led an uprising that resulted in the Kurukove Treaty, which established a registry of $6,000$ men. This was followed by T. Fedorovych in $1630$, leading to the Pereyaslav Agreement which increased the registry to $8,000$ men. In $1635$, Ivan Sulima destroyed the Polish fortress of Kodak, though he was later captured. The final major wave of uprisings occurred in $1637$-$1638$ under leaders P. Pavliuk, Ya. Ostrianyn, and D. Hunia. Following their defeat, the Polish Sejm passed the "Ordinance of the Zaporozhian Host" in $1638$, which limited the registry to $6,000$ and revoked many Cossack rights and privileges, ushering in the period known as the "Golden Peace" ($1638$-$1648$) for the Polish state.

The National-Liberation War and the Leadership of Khmelnytsky

The National-Liberation War ($1648$-$1657$) was sparked by national, religious, social, and military grievances. Ukrainians faced intensified national oppression and lacked their own state; the population was subjected to forced Catholicism; the days of "panshchyna" (corvée labor) were continuously increased; and the szlachta attacked the rights of the Cossacks. The personal pretext (pryvid) for the uprising involved D. Chaplynsky, a Polish official who attacked Bohdan Khmelnytsky's homestead (khutir) in Subotiv, beat his son, kidnapped his wife, and burned his property.

In early $1648$, Khmelnytsky secured the Mykytynska Sich and negotiated the Bakhchysarai Treaty with the Crimean Khanate in February $1648$. This alliance provided essential cavalry support for the Cossack movement. The initial phase of the war was marked by a series of brilliant victories for the Cossack-Tatar forces at Zhovti Vody, Korsun, and Pyliavtsi. By September and October of $1648$, the forces besieged Lviv and Zamost, though they eventually withdrew after the Poles paid a large ransom and a truce was reached. In December $1648$, Khmelnytsky entered Kyiv in triumph.

Treaties and Shifting Alliances ($1649$-$1657$)

In $1649$, after the siege of Zbarazh and the Battle of Zboriv, the Zboriv Treaty was signed. It recognized the Hetmanate's authority over three voivodeships (Kyiv, Bratslav, and Chernihiv), set the registry at $40,000$ men, designated Chyhyryn as the capital, and granted the Orthodox Metropolitan a seat in the Sejm. However, the tide turned in $1651$ at the Battle of Berestechko, where the Crimean Khan betrayed the Cossacks and fled the field, leading to a Cossack defeat and the subsequent Treaty of Bila Tserkva. This treaty reduced the registry to $20,000$ and limited the Hetmanate’s control to the Kyiv voivodeship alone.

Khmelnytsky regained momentum in $1652$ after the Battle of Batoh, which effectively restored the terms of the Zboriv Treaty and led to a dynastic alliance with Moldavia through the marriage of his son, Tymish Khmelnytsky, to Roksanda Lupu. Following the Battle of Zhvanets in $1653$ and another Tatar betrayal, the Kamianets Agreement was reached. On January $8$, $1654$, the Pereyaslav Council took place, where the Hetmanate accepted the protectorate of Moscow. This was codified in the March Articles of $1654$, which set the registry at $60,000$ but also installed a Muscovite voivode in Kyiv and prohibited independent diplomatic relations with the Rzeczpospolita and the Ottoman Empire. The subsequent war from $1654$-$1656$ pitted the Ukrainian-Muscovite alliance against Poland and Lithuania. In $1656$, Moscow and the Rzeczpospolita signed the Truce of Vilna, which Khmelnytsky viewed as a betrayal, leading him to form a new alliance ($1656$-$1657$) with Transylvania and Sweden against Poland.