Polish–Lithuanian Commonwealth: Union, Crisis, Reform and Partitions

The Polish–Lithuanian Commonwealth existed from 1569 to 1795 across a shifting expanse of Central and Eastern Europe, in lands now divided among Poland, Lithuania, Belarus, Ukraine, Latvia and neighboring states. It joined two older political entities: the Kingdom of Poland, usually called the Crown, and the Grand Duchy of Lithuania, whose separate history reached back to the thirteenth century. The Crown and Grand Duchy retained distinct laws, offices and institutions, while their peoples included Poles, Lithuanians and Ruthenians, the East Slavic populations of the eastern lands, as well as Jews, Germans, Tatars and other communities.

Its elected monarch governed alongside a parliament representing the nobility. Agricultural exports enriched landowners and merchants, while peasants supplied much of the labour that sustained estates. Wars brought territorial gains, losses and widespread destruction, and neighbouring powers increasingly intervened in elections and government. The Commonwealth’s final decades saw reforms intended to strengthen administration and defence, followed by invasions and the three partitions that ended the state.

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From medieval partnership to the Union of Lublin

Poland and Lithuania had a changing relationship of rivalry, warfare and alliance before they formed a lasting political union. A succession crisis in Poland in the 1380s helped bring the two rulers closer. After the death of King Louis of Anjou in 1382, Polish lords chose his younger daughter Jadwiga as monarch. They turned to Jogaila, Grand Duke of Lithuania, as a marriage partner and ally. In the Union of Krewo of 1385, Jogaila pledged to adopt Christianity. He married Jadwiga and was crowned King Władysław II Jagiełło in 1386. The arrangement joined the rulers dynastically, but did not immediately merge the two states.

Relations continued to develop through further agreements. In the sixteenth century, Lithuania faced growing pressure on its eastern frontier, while its nobles sought closer ties with Poland and access to the political privileges enjoyed by the Polish szlachta, the landed nobility. Lithuanian leaders resisted proposals that would reduce the Grand Duchy to a province. King Sigismund II Augustus, who ruled both realms and had no heir, pressed for a stronger union.

The Union of Lublin, agreed in 1569, established the Commonwealth as a single political entity. It created a shared monarch, a common parliament and a unified foreign policy. The Crown and Grand Duchy nevertheless remained distinct: Lithuania kept its name, laws and many of its own institutions, including its army and treasury. The union was therefore a close political partnership rather than the disappearance of Lithuania into Poland. Later legal arrangements affirmed the two-part character of the state, even as the Crown held greater population and revenue.

A composite state and an elected crown

When Sigismund II Augustus died in 1572 without an heir, the ruling Jagiellonian dynasty came to an end. The resulting interregnum established the practice of electing each monarch. In the first election, in 1573, nobles who chose to participate selected Henry of Valois, a French prince. Every elected king had to accept the Henrician Articles, a set of fundamental rules limiting royal authority, as well as pacta conventa, individual commitments negotiated with the king-elect.

The General Sejm, or parliament, brought together the king, a Senate and a Chamber of Deputies. It dealt with legislation, taxation, foreign affairs and decisions on war. Local noble assemblies, called sejmiks, selected deputies and could give them instructions. A monarch could not simply impose new taxes or laws without the Sejm’s agreement. Nobles also claimed a right of resistance, known as a rokosz, against a ruler who violated their guaranteed liberties.

This system was often described as the Golden Liberty, but its political participation was limited by social rank. The nobility held the formal rights to elect kings and choose parliamentary deputies. Peasants, townspeople and most other inhabitants did not vote for the national parliament. Nor did the system operate identically in all regions: the Grand Duchy had its own political traditions and administration, while Royal Prussia retained regional privileges within the Crown.

One parliamentary procedure later became especially disruptive. Under the liberum veto, an individual deputy could object to a Sejm decision and bring a session to an end, invalidating its legislation. It came to be used with increasing effect in the seventeenth and eighteenth centuries, sometimes at the urging of magnates or foreign governments. Royal courts, local assemblies and town governments continued to operate, while decisions on national taxation, military funding and reform could be blocked.

Land, commerce and the people of the Commonwealth

Much of the Commonwealth’s economy rested on agriculture. A noble estate often included a folwark, the landowner’s directly managed farm, alongside holdings cultivated by peasant households. The households worked their own plots to obtain food and income, but also owed labour on the lord’s fields. Such service could include ploughing, harvesting or carting with their own animals and equipment. The folwark therefore drew on resources maintained by peasant families as well as on the landlord’s land. Increasing its output could mean increasing the time those families owed to the estate.

Grain, especially rye, was a major export. River transport, notably along the Vistula, carried produce north to the Baltic port of Gdańsk, from where merchants shipped it to markets in western Europe. Timber, cattle, hides, furs, linen and other goods also entered long-distance trade. The Crown’s commercial and urban centers were more developed than the largely rural Grand Duchy, though towns and craft production existed throughout the state. Gdańsk was a major trading port, while Warsaw’s commercial role grew later.

These arrangements created different interests within society. Noble landowners could profit from exports, and magnate families built large estates and networks of dependents. Many townspeople worked as merchants, artisans or laborers, but cities had less political influence than the nobility. Jewish communities, particularly active in trade and crafts, lived in towns and smaller settlements across the Commonwealth. The population also included Catholic, Orthodox and Protestant Christians, as well as Muslim Tatars. Polish and Latin served official functions; Ruthenian was used in the Grand Duchy’s chancellery until 1697, while Lithuanian and other languages remained part of everyday life.

The Warsaw Confederation of 1573 pledged peace among people divided in religion and opposed punishment for differences of faith. In 1596, the Union of Brest brought several Orthodox bishops and their congregations into communion with Rome while retaining an eastern rite. Other Orthodox communities rejected the union, producing rival church organizations. Catholic reform also expanded through schools, preaching and religious orders. In 1658, the Sejm required the Polish Brethren, who rejected the Christian doctrine of one God in three persons, to convert or leave the country, a specific restriction on the earlier settlement of religious peace.

Expansion and strain in the sixteenth and early seventeenth centuries

The late sixteenth and early seventeenth centuries brought military successes as well as expanding commitments. Under Stephen Báthory, the Commonwealth strengthened its position in Livonia and around the Baltic. Under Sigismund III Vasa, it intervened in Russia during the Time of Troubles. Commonwealth forces occupied Moscow for a period after taking the city in 1610, but were driven out in 1612. The Truce of Deulino in 1618 brought substantial eastern territories under Commonwealth control.

Campaigning required taxes, supplies and soldiers from the Crown and Grand Duchy’s separate military systems. In the 1620s, conflict with Sweden brought the loss of much of Livonia. Władysław IV, who became king in 1632, invested in artillery and the army, but large-scale preparations depended on the consent and funding of political institutions. Victories could extend the frontier without securing the revenue needed to defend it.

In the southeastern lands, estate expansion brought landlords into conflict with frontier communities accustomed to military service and greater freedom of movement. Cossacks were armed communities associated especially with the Dnieper frontier. Some served in a royal register, an official list entitling its members to pay and privileges. The first register of 1572 contained 300 men paid in money and cloth. Later arrangements granted registered Cossacks exemptions from taxes, access to land and forms of self-government. Many Cossacks remained outside the register, so the question of who qualified for these rights became a persistent source of conflict.

The wars and rebellions of the mid-seventeenth century

A series of conflicts beginning in 1648 transformed the Commonwealth. Bohdan Khmelnytsky led a Cossack uprising in the Ukrainian lands. Restrictions imposed in 1638 had curtailed Cossack self-government and threatened unregistered Cossacks with the obligations of dependent peasants. These grievances combined with disputes over noble estates and the position of the Orthodox Church. Registered Cossacks joined the rebellion, which also drew substantial support from Ruthenian peasants. An alliance with Crimean Tatars supplied cavalry and helped the insurgents defeat Crown forces.

In 1654, Cossack leaders accepted the protection of the Russian tsar, drawing Russia into war with the Commonwealth. The fighting devastated Ukrainian territories and weakened Crown authority in the east. The Commonwealth’s crisis worsened in 1655, when Sweden invaded in what became known as the Deluge. Swedish forces occupied much of the Crown’s territory, while Russian armies pressed into the Grand Duchy. The wars damaged villages, towns, farms and trade, and brought severe population losses. The conflict also strained the treasury and left soldiers unpaid.

The Commonwealth recovered some of its position, but the settlement came at a lasting cost. Under the agreements of 1657, the ruler of Brandenburg-Prussia gained sovereignty over Ducal Prussia, ending its former dependence on the Commonwealth. The Treaty of Oliva in 1660 concluded the war with Sweden. The Truce of Andrusovo with Russia in 1667 confirmed major eastern losses, including left-bank Ukraine, the lands east of the Dnieper, and territories around Smolensk; Kyiv also passed under Russian control under the truce’s arrangements. The division left Cossack lands divided between the two states.

Wars and political conflict reinforced each other. The government struggled to raise dependable revenue, while magnates gained influence through their estates, private followings and support among less wealthy nobles. Soldiers sometimes formed confederations to demand unpaid wages, adding to disorder. As the liberum veto was used to disrupt parliamentary sessions, it became harder to agree on sustained military and fiscal measures. Interrupted tax decisions and unpaid troops weakened the state’s ability to respond to further campaigns.

Military success and growing vulnerability

John III Sobieski’s election in 1674 brought a capable military commander to the throne. His victory with allied forces at Vienna in 1683, where the Ottoman siege was broken, restored the Commonwealth’s military reputation. Yet the achievement did not reverse the financial and political difficulties that limited the state. The wars against the Ottoman Empire continued, and the Commonwealth’s diplomacy often depended on shifting alliances among neighboring powers.

The Great Northern War, fought from 1700 to 1721, again made Commonwealth territory a battlefield. Augustus II, who also ruled Saxony, entered the war with his Saxon forces, seeking gains on the Baltic. Swedish forces entered the Commonwealth, and rival political groups supported different kings. The wars and civil conflict disrupted towns, farms and trade, while foreign troops and political agents gained influence. In 1717, the Silent Sejm reached a settlement that limited the army and constrained the king’s ability to maintain Saxon troops in the Commonwealth. Russian intervention in the settlement marked a further loss of political independence.

During the eighteenth century, elections increasingly drew in neighboring powers. When Augustus II died in 1733, Russia and Austria backed Augustus III against Stanisław Leszczyński, who had been chosen by many Polish nobles. Russian military intervention helped decide the succession. A contested royal election had become an opportunity for neighbouring armies to determine who occupied the throne.

Foreign intervention and the reforming age

Stanisław August Poniatowski was elected in 1764 with Russian support. He and his allies sought to improve administration, education and the armed forces, but Russia opposed changes that might make the Commonwealth stronger or less dependent. In 1768, the Bar Confederation formed in opposition to Russian influence and the king, claiming to defend the Catholic faith, noble liberties and the country’s independence. Fighting continued for several years. At the same time, a peasant revolt in Ukrainian lands, known as Koliyivshchyna, turned against landlords and their agents, including Jewish tenants and managers. Both movements were suppressed, and civilians suffered in the violence.

In 1772, Russia, Prussia and Austria carried out the First Partition. Prussia took territory that gave it control over much of the lower Vistula, Austria acquired southern lands, and Russia annexed eastern territories. The Commonwealth lost territory, revenue and population, but continued to exist. A Sejm convened under pressure ratified the partition in 1773. That same year it created the Commission of National Education, a state authority that reorganized schools and promoted a broader program of educational reform.

Reformers also sought to make the government more effective. A Permanent Council took on administrative responsibilities, and new commissions supervised areas such as the treasury and military. These changes brought some improvement, but the Commonwealth remained subject to outside interference. In the later eighteenth century, the economy and population began to recover. Manufacturing and trade expanded in some towns, especially Warsaw, while the conditions of rural people remained unequal and serf labor continued to dominate agriculture.

The Constitution of 3 May and the struggle to preserve the state

The Great Sejm, which met from 1788 to 1792, undertook the most ambitious reform effort. The Free Royal Cities Act of 1791 improved the legal and economic position of burghers in royal towns, including their access to public offices and the right to buy rural land. On 3 May 1791, the Sejm adopted a new constitution. It replaced the elective monarchy with hereditary succession, ended the liberum veto, strengthened central government and introduced majority voting for parliamentary decisions. It also placed peasants under the protection of law and government, though it did not abolish serfdom.

The constitution strengthened central government, while the Reciprocal Guarantee of the Two Nations of 20 October 1791 defined Lithuania’s place in shared military and treasury commissions. Equal Crown and Lithuanian representation on these commissions reconciled common administration with the Grand Duchy’s political standing. These changes were contested among nobles and magnates, but they were also a response to the practical difficulty of defending a large country with a weak central government.

Russia opposed the reforms. In 1792, conservative opponents formed the Targowica Confederation and appealed to Russia for assistance. Russian forces invaded, and the king, judging continued resistance futile, joined the confederation. The Second Partition followed in 1793, when Russia and Prussia took further territories. At New Grodno Castle, a Sejm operating under Russian military pressure accepted the partition and dismantled the reform settlement. The castle had been built for Augustus III in the eighteenth century. Its main block was substantially rebuilt after the Second World War, so the present complex includes later changes to the setting of the 1793 proceedings.

Insurrection and the final partition

In March 1794, Tadeusz Kościuszko began an uprising against the partitioning powers. The movement sought to restore independence and drew support from townspeople and peasants as well as nobles. On 7 May, his Proclamation of Połaniec placed peasants under government protection, secured their holdings against arbitrary eviction and reduced compulsory labour during the uprising by one-third to one-half. Men serving in the army were excused that labour. Appointed overseers were to receive complaints and protect compliance with the proclamation. These measures sought to bring rural families into the national struggle by easing obligations that obstructed military service, though landlords resisted their enforcement.

The rebellion spread to Warsaw and the Grand Duchy of Lithuania, but its forces faced better-resourced Russian and Prussian armies. Kościuszko was captured in October, and Warsaw fell in November after Russian troops stormed the Praga district. The uprising’s defeat removed the remaining armed resistance. In 1795, Russia, Prussia and Austria carried out the Third Partition. The Polish–Lithuanian Commonwealth ceased to exist as a state, and its territories were divided among the three powers. King Stanisław August abdicated on 25 November, after the agreement on the Third Partition.