Lithuania and the Devastation of the Great Northern War

Following the devastating wars of the 17th century, including conflicts with Russia, Sweden, and the Cossack uprisings, the Polish-Lithuanian Commonwealth entered the 18th century deeply fragmented. The Treaty of Andrusovo (1667) had left key eastern territories in Russian hands, diminishing the Commonwealth’s influence. Meanwhile, internal factionalism and economic decline left both Poland and Lithuania vulnerable to external manipulation. The Commonwealth's military strength was heavily reduced by these wars, leaving it struggling to maintain unity.

The unexpected election of Augustus II of Saxony in 1697 created a personal union between Saxony and the Polish-Lithuanian Commonwealth, bringing together two politically and economically dissimilar entities. Augustus’ ambitions mirrored those of absolutist rulers like Louis XIV, as he sought to strengthen his authority and reclaim Livonia—lost to Sweden. However, the Polish nobility resisted his efforts, fearing the erosion of their privileges. Augustus stationed the Saxon army within the Commonwealth, which alienated many nobles and deepened internal divisions.

The Great Northern War (1700–1721), which aimed to curb Swedish dominance in the Baltic, became the turning point for the Commonwealth. Augustus allied with Russia and Denmark against Sweden, using the conflict to pursue Saxon and Polish interests in Livonia. However, the war exposed the Commonwealth’s weakened state. The Swedish king, Charles XII, quickly invaded Polish territories, leading to the forced abdication of Augustus and the installation of Stanisław Leszczyński as a puppet king under Swedish influence. This resulted in a civil war within the Commonwealth, as the nobility divided into pro-Saxon and pro-Swedish factions.

Despite Saxony’s recovery after the Battle of Poltava (1709), which ended Swedish dominance, the Commonwealth suffered lasting consequences. The war further weakened Lithuania and Poland, exposing them to Russian interference. The Silent Sejm of 1717, overseen by Tsar Peter I, limited the size of the Commonwealth’s military and marked the beginning of Russia's long-term control over the region. This era signaled the decline of both Lithuania and the Commonwealth as independent powers, as Augustus II's ambitions failed to translate into real influence, leaving the Commonwealth increasingly dependent on external powers.

The Great Northern War Plague outbreak (1708–1712) further devastated the region. This plague, which spread across much of Northern and Eastern Europe, ravaged Poland, Lithuania, and Livonia, decimating civilian populations already weakened by years of war. The disease spread rapidly through military camps, besieged cities, and trade routes, wiping out entire communities. In Vilnius, the capital of the Grand Duchy of Lithuania, the plague killed tens of thousands of residents. Rural areas were also heavily impacted, leading to widespread famine and economic collapse. The outbreak undermined attempts at recovery, as agricultural production halted, and trade was severely disrupted. Lithuania, in particular, never fully recovered from the demographic and economic toll of the plague, which compounded the Commonwealth’s structural weaknesses.

Although Augustus II reclaimed the throne after the defeat of Sweden, the Commonwealth’s long-term decline could not be reversed. The population losses from both the war and the plague outbreak reduced the state's ability to defend itself or rebuild economically. Lithuania’s weakened infrastructure became increasingly dependent on the larger powers of Russia and Prussia. The union with Saxony, initially seen as a potential path to stabilization, instead revealed the Commonwealth’s structural fragility and deepened its reliance on foreign powers—setting the stage for further decline in the decades to come.