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. The Poles successfully resisted the German knights, who eventually had to lift the siege. By the end of 1521 the Teutonic Knights were forced to ask for an armistice and in 1525 the Grand Master of the Order, Albrecht Hohenzollern, paid homage to the Polish king, Sigismund the Old.