Battle of Chojnice (1454) was fought between Poland and the Teutonic Knights during the Thirteen Years' War. The Teutonic army consisted of about 9,000 cavalry and 6,000 infantry under the command of Bernhard von Zinnenberg, while the Polish army had 16,000 cavalry, and over 3,000 infantry troops as well as about 2,000 mercenaries hired by the Prussian Confederacy, all of which were under the command of the Polish King, Casimir IV. At the outset, the Polish cavalry succeeded in breaking through the Teutonic lines, killed Duke Rudolf of Sagan and captured Zinnenberg. The Teutonic cavalry tried to break through the Polish lines but were met with strong Polish defense. But unexpectedly Zinnenberg managed to escape and led the pursuit attacking the Polish troops. When it was all over about 3,000 Polish men died in battle, and 300 were captured by the Teutonic Knights.
Sigismund III Vasa was King of Poland and of the Polish-Lithuanian Commonwealth, and Grand Duke of Lithuania on September 18, 1587. Sigismund was elected to the throne, and sought to establish a union between the Commonwealth and Sweden. He did achieve this goal in 1592. Seven years later, after he was deposed from the Swedish throne by his uncle, Charles IX of Sweden, he spent much of the rest of his life attempting to reclaim it. During his quasi-45 year rule, Sigismund was subjected to criticism in Poland for his unsuccessful decisions that negatively affected the diplomatic and financial situation of the country. But he was also widely praised, in particular by nationalists, for the capture of Moscow, and for obtaining new territories which greatly expanded the Commonwealth to the largest country in Europe during the 16th and 17th century. But the Golden Age of the Commonwealth would end with its final partition in 1795. For the next 123 years, Poland ceased to exist. Sigismund III is commemorated in Warsaw with Sigismund's Column, which was commissioned by his son and successor, Władysław IV.
Battle of Tomaszów Lubelski which took place from September 18 to 20, 1939 near the town of Tomaszów Lubelski was fought between Polish Army Lublin and Army Krakow against German VIII Army Corps and XXII Panzer Corp. Polish forces consisted of five infantry divisions 3rd, 21st, 22nd, 23rd, and 55th and included one of the largest Polish armored units of that time, the Warsaw Armoured Motorized Brigade, as well as the 1st Mountain Brigade and Kraków Cavalry Brigade. The Battle was the second largest fought during the Invasion of Poland (the largest was the Battle of Bzura) and also the largest tank battle of the September campaign. Polish troops attacked the town of Tomaszów on the morning of September 18 and by early afternoon half the town was under Polish control. But they were forced to withdraw after the German 4th Light Division struck Polish units. On the night of September 18-19, the Warsaw Brigade, supported by the 23rd and 55th infantry divisions, made a second attempt to capture Tomaszów in a surprise attack, but failed to achieve their objective. They made a third attempt the next night, but the attempt was disorganized and chaotic and also failed. Polish casualties of killed and wounded kept rising, and ammunition and food supplies were dwindling. Polish General Piskor decided to surrender. After days of heavy fighting, Polish troops were reduced to 30-50% of their original strength (except for the Armoured Brigade). The Battle ended with a decisive German victory. Army Krakow surrendered on September 20, 1939. The Germans took 11,000 Polish soldiers as prisoners, while the remainder escaped into the forests.
The Polish submarine Orzel made a daring escape to England after its crew overpowered two Estonian guards who interred them at Tallinn, in Estonia. As the Orzel emerged in the North Sea, and after having followed a treacherous course around the Baltic coast near Denmark, the vessel was fired upon by British and German warships. She had no means to identify herself as the Estonians had confiscated all equipment, including the radio. She finally made landfall off the coast of Scotland 40 days after she sailed from Gdynia.
The Battle of Wilno was fought between Polish forces and the Soviets, which were invading Poland from the east. On September 18 at approximately 17:00, Okulicz-Kozaryn received reports that Soviet forces were approaching from Oszmiana (today, Ashmyany, Belarus). The first Soviet attack was repelled by Polish defenders though they were greatly outnumbered. Polish troops took some bridges, with the objective of delaying the Soviet advance, but their tactic failed. Soviet troops continued their attack unabated, advanced into Wilno, captured the airfield and the city. By the next day, the Soviet armoured units were reinforced with infantry and cavalry. The Soviets transferred Wilno to the Lithuania authorities, according to the Soviet–Lithuanian Mutual Assistance Treaty. Lithuanian troops entered the city on October 27 to 28, 1939. Polish troops surrendered, others had retreated towards the Lithuanian border or deeper into Poland
The Battle of Kobryń began on September 14, 1939, between the German XIX Panzer Corps of General Heinz Guderian and the improvised Polish 60th Infantry Division "Kobryn" of Colonel Adam Epler. The Polish commander received reports that German troops were advancing rapidly and he surmised that the Germans would advance on the towns of Brześć and Kobryń, as well as toward an important railway node located in the village of Żabinka. The next day the German 3rd Armoured Division destroyed a column of the 9th reserve light artillery depot. By evening, Epler's forces spotted and bombarded by the Luftwaffe. The following day when the main force of the German XIX Corps arrived, the Polish 2nd Battalion of the 84th Infantry Regiment together with an armoured train organised an ambush and attacked the German. After six hours of unrelenting combat, the Germans were forced to retreat suffering heavy casualties. The Polish troops were able to seize a significant number of guns and tanks, but due to lack of fuel had to destroy them, and retreat towards the main Polish defense lines. On September 17, 1939, German units tried to outflank the Poles but had to withdraw under heavy machine gun fire. At the same time, Soviet armies were invading Poland from the east. On September 18 the Germans captured Gubernia I and Gubernia II, but a counterattack from Poles at Kobryn forced the enemy to retreat. The Germans were unable to capture Kobryn because of fierce Polish counterattacks, resulting in an impasse. With the impending invasion of the Soviets, Polish troops withdrew from Kobryn.
Warsaw Uprising. Stalin decided to finally grant the United States Air force clearance to fly one mission to aid the Poles during the Warsaw Uprising. A little over a hundred B-17 Flying Fortresses flew in a daylight mission at high altitude accompanied by P-51 fighters. They dropped 1,284 containers of supplies to the Polish insurgents but only 228 of the containers fell in Polish-controlled territories. The rest were captured by Nazi German troops. This was the only major US supply drop during the war that was permitted by the Soviets. Soviet commanders on the ground near Warsaw estimated that 96% of the supplies dropped by the Americans fell into German hands. From the Soviet perspective, the Americans were (unintentionally) supplying the Nazis instead of aiding the Polish resistance. Following this debacle, the Soviets refused permission for further American flights until September 30. But by the end of September, the weather was too unstable to allow any flights, and the Uprising was nearly over.
Last Russian troops left Poland. After 54 years of Russian occupation, the last remnants of Russian combat troops left Poland on this day. Polish newspapers brandished headlines,"Gone!" and "Soviets Go Home!" It expressed the bitterness of the Polish people of living under Russian totalitarianism for decades, as well as elation of achieving freedom at last. At a press conference leading up to the election the next day, then President Lech Walesa and Prime Minister Hanna Suchocka considered this Russian departure as a great success and that "historical justice is being accomplished". Furthermore, he stated that the Russian withdrawal heralded the end of "agony, humiliation and captivity." However, Walesa was alarmed that former communists were trying to run for political office, and were actually leading in the opinion polls. At a ceremony marking the Russian withdrawal, Walesa spoke about the communist legacy and used it as an attempt to disparage communist political candidates.