sentences:  Thence, it participated in the Baltic Sea trade as a member of the Hanseatic League (from 1386), which led to several conflicts with the competing seaports of at Kołobrzeg and Darłowo.From 1356 until 1417/1422, the city was part of the Duchy of Pomerania-Wolgast.In 1446 Koszalin fought a victorious battle against the nearby rival city of Kołobrzeg.