How Lithuania Lost Half Its Territory on the Way to a Union — and What UsefulCharts Left Out
In Matt Baker's Polish & Lithuanian Monarchs Family Tree, one of the most consequential political confrontations in European history receives a remarkably peaceful description.
Baker explains that, in 1569, Poland and Lithuania were officially merged into a single country, creating the Polish–Lithuanian Commonwealth. The new state, he adds, was larger than the Holy Roman Empire.
Both statements are broadly defensible.
What disappears is the price of the agreement.
Before the Union of Lublin was signed, King Sigismund II Augustus transferred vast territories from the Grand Duchy of Lithuania to the Polish Crown. Lithuanian representatives had walked out of negotiations. The king responded by changing the borders of the territories they represented.
Historian Robert Frost, in The Oxford History of Poland-Lithuania, estimates that Lithuania lost approximately half its territory through these incorporations. The resulting agreement recognized the continued existence and constitutional standing of both Poland and Lithuania, but it was negotiated after a substantial redistribution of land and power.
That is the story Baker leaves untold.
His video is a genealogy, not a documentary devoted exclusively to constitutional history. Compression is unavoidable. But when a creator moves beyond succession to explain the formation of a major European state, omitting the confrontation that shaped its creation becomes more than a harmless simplification.
It changes what the audience understands about the event.
The Alliance Was Negotiated Under Military Pressure
Poland and Lithuania had been connected through dynastic arrangements since the marriage of Jogaila and Jadwiga in the 1380s. Their shared rulers helped maintain cooperation while the two countries preserved distinct political institutions.
By the sixteenth century, that arrangement was becoming increasingly difficult to sustain.
Lithuania faced an expanding Muscovite state. Its eastern territories had suffered substantial losses, and the struggle for control of Livonia placed additional pressure on its military resources.
In 1563, the forces of Ivan IV captured Polotsk, a strategically important Lithuanian city. The defeat made Lithuania's need for Polish military and financial assistance more urgent.
Meanwhile, Sigismund II Augustus had no surviving children. The Jagiellonian dynasty was approaching extinction, threatening the continuity of a political relationship that depended heavily on shared rulers.
The king wanted a more permanent union. Polish nobles sought greater access to Lithuanian politics and property. Lithuanian magnates wanted military assistance without surrendering the independence of their institutions.
These interests overlapped, but they were not identical.
Baker explains the succession problem. He does not explain the military and political pressures that determined how the solution was negotiated.
That omission matters because a country negotiating while its territories are under attack does not possess the same freedom of action as a country bargaining from security.
There is an important limit to this argument. Lithuanian historians do not universally accept that Lithuania faced inevitable conquest by Moscow without the union. Gintautas Sliesoriūnas has specifically questioned whether the evidence justifies that conclusion.
The military danger was real. Inevitable national destruction was not an established fact.
It was nevertheless a serious vulnerability, and Sigismund knew it.
When Lithuania Walked Out, the King Changed the Map
The decisive negotiations began at Lublin in January 1569.
Polish representatives pressed for a closer political union. Some favored arrangements that would effectively eliminate Lithuania's separate statehood.
Lithuanian delegates resisted. Their position was not necessarily opposition to every form of union; they wanted guarantees that Lithuania would remain a distinct political entity.
Mikołaj Radziwiłł the Red emerged as an important leader of the Lithuanian resistance.
On March 1, the Lithuanian delegation abandoned the negotiations.
The walkout was intended to resist unacceptable terms. Instead, it exposed the delegates to a devastating response.
Sigismund Augustus, simultaneously King of Poland and Grand Duke of Lithuania, ordered the transfer of territories belonging to the Grand Duchy into the Polish Crown.
Podlasie and Volhynia were incorporated, followed by Bratslav and Kyiv.
These were not small border adjustments. They included extensive Ruthenian territories, much of which lies within present-day Ukraine.
The incorporations occurred through decisions by the common monarch, under pressure from competing political interests. They should not be confused with a separate Polish military conquest of Lithuania.
But the practical result was unmistakable: Lithuania's negotiating position had been weakened by the loss of territory.
The Lithuanian delegation eventually returned, now led by Jan Hieronim Chodkiewicz.
Its leaders hoped further negotiations might reverse the territorial transfers. That hope was disappointed.
The union was concluded on July 1, 1569. The transferred territories remained under the Polish Crown.
This is the sequence missing from Baker's account.
First came disagreement.
Then the Lithuanian walkout.
Then the territorial transfers.
Then renewed negotiations.
Finally, agreement.
Calling the outcome a merger without describing this sequence removes the mechanism through which the final settlement became possible.
The king did not merely persuade the parties to accept a new constitutional arrangement. He altered their negotiating positions before they reached it.
The People of Ukraine Were Not Simply Lithuanian Property
There is another danger in telling this story exclusively as Poland exploiting Lithuania.
It risks making the same mistake Baker makes: treating enormous territories as possessions transferred between rulers while leaving their inhabitants outside the narrative.
The lands incorporated into Poland in 1569 contained substantial Ruthenian populations, including ancestors of modern Ukrainians.
Their political elites had interests distinct from those of Lithuanian magnates.
Some Ruthenian nobles welcomed closer association with Poland because it offered access to political rights, economic opportunities, and forms of noble self-government they considered advantageous.
Volhynian representatives initially resisted straightforward incorporation. They subsequently negotiated guarantees for regional privileges and legal autonomy.
Historian Tomasz Kempa's research demonstrates that Ruthenian princes and noblemen played an active role in shaping the settlement. They were not simply spectators to an agreement between Poles and Lithuanians.
Their support helped make the territorial incorporations politically sustainable.
This complicates any convenient account of Polish aggression against a uniformly unwilling Lithuanian state.
Lithuanian leaders resisted losing territory.
Some Ruthenian elites preferred transferring their political allegiance.
Polish nobles anticipated opportunities from a closer union.
The king pursued a more durable political structure.
These competing interests produced the Commonwealth.
A good historian should resist turning that complexity into a simple story of national victims and national victors.
Yet Baker's account does not even introduce the disagreement.
The omission is particularly consequential because the territorial transfers changed the future political environment of lands that would become central to Ukrainian history.
Kempa identifies the acceleration of Polonization after 1569, alongside the preservation of significant Ruthenian legal and cultural autonomy.
Later religious disputes, including those surrounding the Union of Brest in 1595–1596, contributed to the development of distinct Ruthenian political and religious identities.
Orthodox nobles and, subsequently, Cossack communities became important defenders of those identities.
Baker eventually discusses the Cossack uprisings that helped weaken the Commonwealth in the seventeenth century.
He describes their devastating consequences, including massacres of Jewish communities.
But his account offers almost nothing about the earlier political rearrangement of the Ukrainian lands or the changing relationships between Ruthenian elites, Polish institutions, and religious authorities.
The Union of Lublin did not single-handedly cause the later uprisings. The historical developments were too complex for that conclusion.
Nevertheless, the territorial and political settlement of 1569 belongs in the background of those later conflicts.
Without it, the viewer encounters the consequences of tensions whose development has barely been explained.
Lithuania Did Not Disappear Into Poland
Baker's description of the Commonwealth as a single country is not, by itself, an error.
The original Act of Union explicitly declared the two realms united in one political body.
But the agreement also preserved their institutional distinctions.
The Commonwealth would have one elected monarch, one common parliament, and coordinated foreign policy.
Poland and Lithuania nevertheless retained separate armies, treasuries, judicial systems, administrative offices, and legal institutions.
The common monarch remained both King of Poland and Grand Duke of Lithuania.
These arrangements are documented in the original union act and examined in research published by Vilnius University.
The constitutional settlement therefore produced something considerably more complicated than the straightforward disappearance of two countries into one.
It established a common political structure while preserving two constituent states.
And Lithuania's political leadership did not abandon its grievances once the treaty was signed.
During the royal interregnums between 1572 and 1588, Lithuanian nobles repeatedly sought to recover transferred territories and strengthen the Grand Duchy's autonomy.
They failed to regain the lost provinces.
They did, however, preserve and develop important elements of Lithuanian political independence within the Commonwealth.
The Third Lithuanian Statute, confirmed in 1588, reinforced the Grand Duchy's distinct legal and constitutional position.
Kempa documents these efforts through contemporary sources, identifying the Radziwiłł family and Jan Chodkiewicz among the prominent figures involved.
This is an extraordinary qualification to the idea of a simple merger.
Almost twenty years after the union, Lithuanian leaders were still fighting over its terms.
They did not necessarily want to destroy the Commonwealth. They wanted a stronger position within it.
A political settlement can produce a functioning state without settling the grievances that accompanied its creation.
That distinction is fundamental to understanding the Polish–Lithuanian Commonwealth.
The Treaty Also Protected Property and Privilege
The original union agreement contains another revealing detail.
Its provisions extended the ability of Polish nobles to acquire property in Lithuania and recognized corresponding rights for Lithuanians in Poland.
The agreement also addressed customs duties, commercial restrictions, and the protection of established noble privileges.
These provisions mattered because the union changed more than the location of political authority.
It affected who could own property, operate across borders, participate in institutions, and exercise influence throughout the combined state.
The treaty's provisions concerning landholding and taxation are particularly revealing. They demonstrate the importance of elite economic interests alongside dynastic and military considerations.
The political freedoms of the Commonwealth were substantial by contemporary European standards.
But those freedoms were concentrated among privileged estates.
The agreement was not an exercise in universal democratic consent. It was negotiated by monarchs, magnates, noble representatives, and other recognized political authorities.
That does not make its achievements imaginary.
It does mean that describing the Commonwealth's creation without identifying the groups whose privileges were protected gives readers an incomplete picture of its political character.
Even the celebrated idea of a Commonwealth of Two Nations requires care.
Its political terminology did not correspond neatly to the modern ethnic nations of Poland and Lithuania. Ruthenians and other communities participated in a political world whose institutions and identities cannot be reduced to two present-day national categories.
A family tree naturally concentrates attention on monarchs.
The difficulty begins when the actions of monarchs become the entire explanation of political change.
The Strongest Defense of the Union Makes the Omission Worse
The Union of Lublin was not merely an act of domination.
It created an enduring political structure that accommodated distinct legal traditions, languages, political communities, and institutions.
Robert Frost's research emphasizes an important historical paradox.
Although Lithuania suffered enormous territorial losses, its representatives secured recognition of a union between two realms of equal constitutional standing.
In that respect, Lithuania achieved an important negotiating victory despite entering the settlement from a weakened position.
Lithuanian historian Rimvydas Petrauskas similarly argues that the agreement should be understood as a difficult compromise rather than merely a Polish victory and a Lithuanian defeat.
He describes the emotional atmosphere of the final negotiations, including a speech by Chodkiewicz that reportedly moved participants to tears.
The Commonwealth subsequently developed a long history of political cooperation.
These facts limit the indictment.
They prevent me from describing the union as simply an annexation disguised as a treaty.
But they also expose the weakness of Baker's presentation.
The extraordinary feature of the settlement was precisely that territorial coercion and constitutional compromise existed together.
Lithuania lost enormous territories yet survived as a distinct political entity.
Poland acquired new provinces but did not entirely absorb the Grand Duchy.
Ruthenian nobles gained negotiated privileges while their lands entered a different political jurisdiction.
The Commonwealth strengthened cooperation without abolishing every division between its constituent territories.
This is a far more revealing historical development than a change of color on a map.
It explains why the union could be remembered both as a major political achievement and as a painful territorial loss.
The Trouble With a Beautifully Finished Picture
In 1869, three centuries after the Union of Lublin, Polish painter Jan Matejko produced a monumental painting commemorating the agreement.
Its central figure is Sigismund Augustus, raising a crucifix before assembled dignitaries.
The painting depicts the solemn moment of union, not the entire process that preceded it.
The National Museum–Palace of the Grand Dukes of Lithuania identifies the work as a major nineteenth-century commemoration of the historical event.
Matejko's painting and Baker's family tree belong to very different forms of historical storytelling.
Yet both demonstrate the same limitation of presenting history primarily through its completed arrangements.
The observer sees the agreement.
The arguments that produced it are less visible.
The resulting picture is orderly. The actual negotiations were not.
There is nothing inherently dishonest about illustrating a historical settlement through its concluding ceremony or its surviving institutions.
The problem arises when the completed arrangement is presented without enough of the preceding conflict to explain its meaning.
That is where Baker's account falls short.
Verdict: A Union Without Its Price
Matt Baker is correct that the Union of Lublin created the Polish–Lithuanian Commonwealth in 1569.
He is correct that it transformed the relationship between the two countries and established a political entity of exceptional size and significance.
What his account fails to communicate is how that transformation was achieved.
Lithuania faced military pressure from Muscovy.
Its representatives resisted the proposed terms.
They abandoned negotiations.
Their shared monarch transferred extensive Lithuanian territories to the Polish Crown.
They returned to negotiate a settlement that preserved Lithuania's constitutional standing but did not restore the lands it had lost.
The resulting Commonwealth endured for more than two centuries, demonstrating that an agreement reached under pressure could nevertheless establish a workable political order.
None of this requires inventing a conspiracy, denying the union's achievements, or accusing Baker of deliberate deception.
The historical record supplies a more serious criticism.
By explaining the Commonwealth's creation almost entirely as a dynastic development, Baker leaves out the struggle over territory, privilege, and political survival that determined its actual terms.
His family tree tells us who ruled Poland and Lithuania.
It tells us considerably less about what those rulers were prepared to do to bring their countries together.
And in 1569, that difference meant half of Lithuania's territory.
References
1. Matt Baker — Polish & Lithuanian Monarchs Family Tree. UsefulCharts, August 1, 2025.
Original video
The original work under review establishes Baker's description of the Union of Lublin and the limited attention given to its negotiations.
2. Act of the Union of Lublin. July 1, 1569; English translation published by Polish Freedom, based on the historical document preserved in Polish archival collections.
Read the original treaty in English
The primary document establishes the Commonwealth's constitutional arrangements, common institutions, protection of privileges, and provisions concerning land ownership.
3. Robert Frost — The Oxford History of Poland-Lithuania, Volume I: The Making of the Polish-Lithuanian Union, 1385–1569, Chapter 39, “Lublin.” Oxford University Press, 2015.
Oxford Academic
The chapter's published abstract confirms the Lithuanian walkout, territorial incorporations, loss of approximately half the Grand Duchy's territory, and subsequent recognition of constitutional equality; the full chapter was not available for examination.
4. Henryk Litwin — “450th Anniversary of the Union of Lublin.” Polish Institute in Kyiv, July 1, 2019.
Read the historical analysis
The account reconstructs the geopolitical pressures, competing negotiating positions, territorial transfers, Ruthenian responses, and Commonwealth institutions; its Polish institutional setting should be considered when evaluating its interpretation.
5. Tomasz Kempa — “The Attitude of Ruthenian Magnates and Nobles toward the Union of Lublin (1569) and the Problem of the Autonomy of Ukrainian Lands within the Polish-Lithuanian Commonwealth.” Zapiski Historyczne, 2019.
Academic publication and abstract
The research establishes that Ruthenian nobles pursued distinct interests, supported important elements of the territorial settlement, and negotiated autonomy while the union accelerated longer-term cultural changes.
6. Tomasz Kempa — “The Issue regarding the Reform of the Union of Lublin in Lithuanian Policy in the Period of Three Interregna Following the Death of King Sigismund Augustus (1572–1588).” Zapiski Historyczne, 2014.
Academic publication and abstract
The study documents Lithuanian attempts to recover transferred territories, renegotiate the union, and strengthen the Grand Duchy's autonomy, including developments culminating in the Third Lithuanian Statute.
7. Rimvydas Petrauskas — “The Union of Lublin, or Why Did the Lithuanians and Poles Weep in Lublin?” Orbis Lituaniae, Vilnius University historical project, undated.
Read the historical essay
The account provides the Lithuanian perspective on the negotiations, Chodkiewicz's emotional speech, and the interpretation of the union as a difficult but durable political compromise.
8. Gintautas Sliesoriūnas — “‘A Tragedy’, But ‘Very Beneficial’: The Evaluation of the Lublin Union in the Latest Lithuanian Historiography.” Parliamentary Studies, 2021.
Read the scholarly abstract
The study challenges overconfident claims that Lithuania faced inevitable annexation by Moscow without the union, limiting what can responsibly be concluded about the alternatives available in 1569.
9. Stanisław Dubisz — “‘Establishment of the Polish-Lithuanian Commonwealth’: A Philological Commentary to the 1569 Union of Lublin Act.” Vilnius University Open Series, February 22, 2021.
Read the academic commentary
The analysis confirms that the union established shared institutions while preserving distinct armies, treasuries, judicial systems, and offices.
10. National Museum–Palace of the Grand Dukes of Lithuania — “Lublin: City of the Union of Lithuania and Poland.” Exhibition information, 2019.
Read the exhibition history
The museum documents Jan Matejko's nineteenth-century painting of the union and identifies its focus on the ceremonial conclusion of the 1569 agreement.