On 22 January 1945 , near the end of the war , Allenstein was plundered and burned by the conquering Soviet Red Army , and much of its German population fled . On 2 August 1945 , the city , even though having had a German-speaking majority , became part of Poland under border changes promulgated at the Potsdam Conference , and former " Allenstein " officially became Polish " Olsztyn " . In October 1945 , the remaining German population was forcibly expelled , to replace the former majority town 's population with new Polish settlers A tyre factory was founded in Olsztyn in 1967 . Its subsequent names included OZOS , Stomil and Michelin
Potsdam Conference
Potsdam Conference
Olsztyn