Kościuszko was born on February 1746 in the Polish-Lithuanian Commonwealth. At the age of 20 he graduated as captain from the Corps of Cadets in Warsaw – an elite school established to train Poland’s best officers. He continued his education in Paris, France where he was enrolled in military lectures, architecture courses, and drawing and painting classes.
In 1772, the First Partition of Poland took place, this involved Russia, Prussia and Austria annexing a huge part of Polish territory. Three years after this tragic event Kościuszko returned to Poland, however he could’t afford to buy his officer’s commission. To do so, he became a tutor in a house of the magnate Józef Sylwester Sosnowski, and soon after he fell in love with his daughter. Sosnowski did not accept their relationship and Kościuszko was forced to leave their house.
Source: Kazimierz Wojniakowski [Public domain], via Wikimedia Commons
In 1776, Kościuszko had heard stories about the American Revolutionary War and decided to support the American cause for freedom. Eventually, he departed for Philadelphia, at the time it was the capital of the American Revolution. On August 30 he submitted an application to the United States Congress, and with the support of Benjamin Franklin (who examined Kościuszko’s knowledge and skills) was allowed to joined the US Continental Army. He would serve as the fortification engineer.
Fame and respect from US soldiers soon came his way after his contribution to the victory at the battle of Saratoga. He chose a convenient place to accept the battle and strengthened the terrain, correctly emplaced all heavy weapons and even connected all key points of American fortifications by building roads. During the preparations of this area US soldiers regained their fighting spirit. The battle of Saratoga was won, and this victory was a breaking point for the Revolutionary War.

A fragment of the Racławice Panorama painting
Source: Own photo
Kościuszko’s success was recognized by George Washington himself, who demanded that responsible tasks should be entrusted to the Polish engineer.
His next big task was to fortificate West Point, on the Hudson river. After 2,5 years of work, West Point was literally turned into a fortress.
Kościuszko’s knowledge and dedication to the US cause was rewarded with a nomination for Brigadier General of the United States Army. He also received about 450 hectares of land and a large sum of money. Later, he allocated this money for the liberation of a large number of black slaves. A big honor for Kościuszko was his adoption, as one of only three foreigners, to the Society of the Cincinnati. This organisation consisted of the most distinguished American officers.
In 1784, Tadeusz Kościuszko returned to Poland. The political situation in the country continued to deteriorate – Russia, Prussia and Austria controlled large plot of Polish land and interfered with Polish politics. The country itself was weak, and the army was reduced. Kościuszko spent 5 years waiting for an opportunity to join the Polish Army.
At this time Polish Parliament tried to reform and strengthen the Republic. On the 12th of October 1789, Kościuszko received an appointment to major General of the Royal Army from the king of Poland.

A fragment of the Racławice Panorama painting
Source: Own photo
These reforms strengthened the country and raised worry among Prussia, Russia and many Polish magnates, siding with occupants. At their request, Russian empress Catherine II sent her army to Polish borders and then attacked. The Polish Royal Army did not have enough men and equipment to stop them.
However, on June 18th, the Poles defeated Russians near Zieleńce. One of the Polish commanders during that battle was Kościuszko himself. After the clash he was amongst 15 soldiers rewarded the Virtuti Militari – Polish highest military decoration for heroism and courage. After a series of battles on the line of the Bug river (battles where Poles stopped a force three times bigger than theirs), Kościuszko was awarded the Order of the White Eagle.
Despite those series of occurrences, the war was lost. The occupants proceeded with the Second Partition of Poland – soon after only a scratch of land remained as the last piece of Polish territory. Poles begun to plan an armed uprising against the occupants. Tadeusz Kościuszko was chosen to be a leader of the forthcoming events. On 24th of March 1794, on the Kraków City Square, he made the famous solemn oath as Supreme Commander of the National Forces, calling the nation to declare war against the invaders.
Source: Jan Bogumił Plersch [Public domain], via Wikimedia Commons
After the battle, Kościuszko published the Proclamation of Połaniec – a famous document which abolished serfdom in Poland, granting substation civil liberties to all the peasants. There were two reasons behind it – Kościuszko was a reformer who believed that freedom was a right of every human. Secondly, his purpose was to encourage peasants to join the Uprising.
By Image taken by User:Mathiasrex Maciej Szczepańczyk (Own work) [CC BY 3.0]
Eventually, the Third Partition of Poland took place, eliminating Poland as a country. Shortly after Kościuszko was captured by Russians where he was subjected to numerous interrogations and investigations. Finally, after he was released from capture, including 20,000 other Poles, he was forced to swear his loyalty to the new Russian Emperor and stop any future attempts of uprising. He would eventually settle in Paris where he tried to rally help for the Polish cause. Aid never came to Poland. In fact, it isn’t until about a hundred years later that Poland would finally regain her independence. Kosciuszko spent the last years of his life in Switzerland, where he died on 1817.
Source: Wizzard (Own work) [Public domain], via Wikimedia Commons
Thanks to Piotr Ziemkiewicz for his help with writing the article.