The Thirteen Years' War yielded great benefits for the transformation of Danzig (formerly Gdansk) into an independent city-state under the protection of the Polish crown and the capture of other Knights territories.
The Polish crown sanctioned three independent city-state areas, including Danzig. 
mnli hypothesis: The Polish crown sanctioned three independent city-state areas, including Danzig.  premise: The Thirteen Years' War yielded great benefits for the transformation of Danzig (formerly Gdansk) into an independent city-state under the protection of the Polish crown and the capture of other Knights territories.