On March 18, 1921, Poland and Soviet Russia signed the Peace of Riga, also known as the Treaty of Riga, in the Latvian capital, thus putting an end to the Polish-Soviet war.
After over a century of partition, Poland regained its independence in the aftermath of the World War I, as a result of the collapse of the Tsarist Empire and the disintegration of the Kingdom of Prussia and Austria-Hungary in Central Europe.
But until the Paris Peace Conference and Treaty of Versailles formally established Poland as an independent state, many territorial issues remained unresolved and fighting for the borders of the reborn nation dragged on even after the Armistice was signed in November 1918.
The Polish-Soviet war
Under the leadership of its new Chief of State Józef Piłsudski, the young Polish state solidified its independence in a series of conflicts that re-defined the country’s borders. War with Ukraine expanded the Polish republic’s territory to include Volhynia and parts of Galicia, while the Greater Poland uprising succeeded in attaching most of the province’s territory to Poland.
Meanwhile, in neighbouring Russia, the Bolsheviks had gained the upper hand in the Civil War and Vladimir Lenin began viewing Poland as a bridge to bring communism to Central and Western Europe. In his speeches, he asserted that the revolution was to be carried to Europe on the bayonets of Russian soldiers and that the shortest route to Berlin and Paris was through Warsaw.
Given that Russia had been one of the three empires that had partitioned Poland at the end of the 18th century, Polish sentiments toward Russians couldn’t have been worse upon regaining independence. And the fact that the former empire was now led by Bolshevik revolutionaries did very little to change these negative outlooks on all things Russian.
Though war between Poland and Russia officially broke out in February 1919, most of the major fighting took place in 1920, after Józef Piłsudski formed an alliance with the exiled Ukrainian leader Symon Petlyura and their combined forces began to push into Belarus and Ukraine, even liberating Kyiv in May.
Despite early setbacks, the Red Army launched a successful counter-offensive, forcing the Polish army to retreat westward in disarray and blocking its eastward invasion of Ukraine and Belarus. By August, Russian forces were already preparing to start the final assault on Warsaw, forcing Piłsudski to launch his counter-attack twenty-four hours early for fear the capital city might fall.
The Battle of Warsaw and the Peace of Riga
The counter-offensive at the Battle of Warsaw, also known as the “Miracle on the Vistula”, resulted in a major victory for Polish forces which, despite suffering about 20,000 casualties, drove the Red Army so far back that the Soviet eventually sued for peace not long after.
The fighting with the Soviets was hugely symbolic for the newly-formed Poland because it reignited a fierce sense of nationalist pride among Poles as the defenders of Europe. Nationalists have even been known to draw comparisons between the Polish-Soviet War and Jan Sobieski III’s defence of Vienna from the Ottomans.
Peace talks began in Minsk as early as August 1920, before being eventually moved to Riga. Armistice was signed in October of that year, but negotiations continued for several months over how to partition the disputed territories in Ukraine and Belarus.
On March 18, 1921, Poland and Soviet Russia signed the Peace of Riga in the Latvian capital, redrawing and securing Poland’s eastern borders until 1939. Thanks to its military successes, the young Polish Republic even gained 200 km of territory east of its former borders, in what is today part of western Belarus and western Ukraine.
Reluctant to recognise the terms of a peace deal concluded without their participation or approval, Allied Powers in the West eventually supported it in 1923. The treaty also faced heavy criticism in signatory countries themselves: not only in Russia, where it appeared to permanently bury the Bolsheviks’ ambition to export their revolution westward, but also in Poland and Ukraine, where the Peace of Riga was seen as a betrayal of the Polish-Ukrainian alliance and of Ukraine’s independentist movement.
Some historians have also highlighted that the redrawn borders provided fertile ground for ethnic tensions in the region, on top of being “militarily indefensible” – two claims that would tragically prove all too accurate over the following decades.
Find out more about Central European history in our On this Day series.
Kafkadesk 
On March 18, 1921, Poland and Soviet Russia signed the Peace of Riga, also known as the Treaty of Riga, in the Latvian capital, thus putting an end to the Polish-Soviet war.
After over a century of partition, Poland regained its independence in the aftermath of the World War I, as a result of the collapse of the Tsarist Empire and the disintegration of the Kingdom of Prussia and Austria-Hungary in Central Europe.
But until the Paris Peace Conference and Treaty of Versailles formally established Poland as an independent state, many territorial issues remained unresolved and fighting for the borders of the reborn nation dragged on even after the Armistice was signed in November 1918.
The Polish-Soviet war
Under the leadership of its new Chief of State Józef Piłsudski, the young Polish state solidified its independence in a series of conflicts that re-defined the country’s borders. War with Ukraine expanded the Polish republic’s territory to include Volhynia and parts of Galicia, while the Greater Poland uprising succeeded in attaching most of the province’s territory to Poland.
Meanwhile, in neighbouring Russia, the Bolsheviks had gained the upper hand in the Civil War and Vladimir Lenin began viewing Poland as a bridge to bring communism to Central and Western Europe. In his speeches, he asserted that the revolution was to be carried to Europe on the bayonets of Russian soldiers and that the shortest route to Berlin and Paris was through Warsaw.
Given that Russia had been one of the three empires that had partitioned Poland at the end of the 18th century, Polish sentiments toward Russians couldn’t have been worse upon regaining independence. And the fact that the former empire was now led by Bolshevik revolutionaries did very little to change these negative outlooks on all things Russian.
Though war between Poland and Russia officially broke out in February 1919, most of the major fighting took place in 1920, after Józef Piłsudski formed an alliance with the exiled Ukrainian leader Symon Petlyura and their combined forces began to push into Belarus and Ukraine, even liberating Kyiv in May.
Despite early setbacks, the Red Army launched a successful counter-offensive, forcing the Polish army to retreat westward in disarray and blocking its eastward invasion of Ukraine and Belarus. By August, Russian forces were already preparing to start the final assault on Warsaw, forcing Piłsudski to launch his counter-attack twenty-four hours early for fear the capital city might fall.
The Battle of Warsaw and the Peace of Riga
The counter-offensive at the Battle of Warsaw, also known as the “Miracle on the Vistula”, resulted in a major victory for Polish forces which, despite suffering about 20,000 casualties, drove the Red Army so far back that the Soviet eventually sued for peace not long after.
The fighting with the Soviets was hugely symbolic for the newly-formed Poland because it reignited a fierce sense of nationalist pride among Poles as the defenders of Europe. Nationalists have even been known to draw comparisons between the Polish-Soviet War and Jan Sobieski III’s defence of Vienna from the Ottomans.
Peace talks began in Minsk as early as August 1920, before being eventually moved to Riga. Armistice was signed in October of that year, but negotiations continued for several months over how to partition the disputed territories in Ukraine and Belarus.
On March 18, 1921, Poland and Soviet Russia signed the Peace of Riga in the Latvian capital, redrawing and securing Poland’s eastern borders until 1939. Thanks to its military successes, the young Polish Republic even gained 200 km of territory east of its former borders, in what is today part of western Belarus and western Ukraine.
Reluctant to recognise the terms of a peace deal concluded without their participation or approval, Allied Powers in the West eventually supported it in 1923. The treaty also faced heavy criticism in signatory countries themselves: not only in Russia, where it appeared to permanently bury the Bolsheviks’ ambition to export their revolution westward, but also in Poland and Ukraine, where the Peace of Riga was seen as a betrayal of the Polish-Ukrainian alliance and of Ukraine’s independentist movement.
Some historians have also highlighted that the redrawn borders provided fertile ground for ethnic tensions in the region, on top of being “militarily indefensible” – two claims that would tragically prove all too accurate over the following decades.
Find out more about Central European history in our On this Day series.