Battle of Mikołów The Battle of Mikołów ( ) refers to the border engement on September 1 and 2 , 1939 , that took place in the area of the town of Mikołów , which is located in the Polish part of Upper Silesia , during the early stages of the Invasion of Poland in the Second World War . Introduction . The battle began with attacks by aircraft of the German 4th Air Fleet ( Luftflotte ) , which bombed several areas , including the airfield in Katowice . Soon afterwards , early in the morning on September 1 , 1939 , units of the " Wehrmacht " crossed the Polish - German border . The invaders were helped by members of the German minority in Poland , whose paramilitary organization , the " Freikorps " , attacked Polish units from the rear . Several skirmishes took place , most of them in the densely populated industrial areas of the cities of Ruda Śląska , Chorzów and Katowice . However , the main German attack was concentrated in the south of the industrial region , around the border towns of Mikołów and Pszczyna . There , units of the Polish Operational Group Silesia ( part of the Krakow Army ) , faced the German 8th Infantry Division ( General Erwin Koch ) , the 28th Infantry Division ( Gen . Hans von Oberstfelder ) and the 5th Armored Division . These formations were all part of the VIII Corps . September 1 , 1939 . The German 5th Armored Division , attacking towards Rybnik and Żory , managed to annihilate the Polish defenders in the morning . The units destroyed by the attackers were located in the Pszczyna Forest , their task was to provide a connection between Operational Groups ' Silesia ' and ' Bielsko ' . Their loss created a gap in the Polish defense , and the Germans took advantage of it on the following day . Despite desperate fighting , the Polish 55th Infantry Division ( under General Jan Jagmin - Sadowski ) , were unable to halt the invaders . September 2 , 1939 . The Germans preceded their main attack with an artillery bombardment from 5 a . m . Later on that day , two German battalions ( 49th and 83rd ) moved towards Tychy , they were faced by Polish units , in the area of the village of Zwakow . The battle that followed was one of the most ferocious of all those that took place in September 1939 in Upper Silesia . Polish units managed to halt the Germans , preventing them from capturing the town of Wyry . Nevertheless , in the afternoon of September 2 , even though the frontline was stabilized , the headquarters of the Armia Kraków ordered all units to leave Upper Silesia and withdraw towards Kraków and the Vistula river . This decision was undertaken because the Germans , attacking in the area of Woźniki , broke the defenses of the Kraków Cavalry Brigade . Also in the south the Germans broke the Polish positions , and the Polish 6th Infantry Division hastily retreated towards Oświęcim . Thus , units in the area of Pszczyna and Mikołów were threatened with encirclement . Withdrawal . A withdrawal order reached all Polish units by 9 p . m . on September 2 . Most soldiers did not believe it , however they obeyed and the whole operation was carried out good in order . Polish troops left Upper Silesia by September 3 , heading towards Kraków . Most of these units found themselves in the area of Lublin , where they took part in the Battle of Tomaszów Lubelski . Among Polish units that distinguished themselves in the Battle of Mikołów , there was the 73rd Infantry Regiment from Katowice . Consisting of soldiers from Silesia , it was regarded as one of the best organized and toughest of the whole Polish Army .