The war began in 1361, when Danish king Valdemar Atterdag conquered Scania, Öland, and Gotland with the major Hanseatic town Visby. In 1362, a Hanseatic counterstrike was repelled by the Danish fleet at Helsingborg, which led Hansa to accept a truce culminating in the unfavourable Treaty of Vordingborg (1365), depriving the league of much of its privileges. Unwilling to accept the treaty, the Hanseatic League, which used to be a trade league rather than a political union, raised a fleet through the Confederation of Cologne in 1367 and renewed their Swedish alliances. In the following battles, Valdemar and his Norwegian son-in-law Hakon VI were utterly defeated.