You may also be looking for the Battle of Allenstein.The Siege of Allenstein or the Siege of Olsztyn took place from January 1521 to February 1521, during the Polish–Teutonic War (1519–21). The town of Olsztyn (Allenstein) was defended by Polish forces against those of the German Monastic Order of the Teutonic Knights. The defense of the town was successfully organized and coordinated by Polish astronomer and scholar Nicolaus Copernicus.