 Complete the following phrase:  After a series of Polish-Teutonic Wars, in the Treaty of Kalisz 1343 the Order had to acknowledge that it would hold Pomerelia as a fief from the Polish Crown. Although it left the legal basis of the Orders possession of the province in some doubt, the city thrived as a result of increased exports of grain especially wheat, timber, potash, tar, and other goods of forestry from Prussia and Poland via the Vistula River trading routes, although after its capture, the Teutonic Knights tried to actively reduce the economic significance of the town. While under the control of the Teutonic Order German migration increased. The Orders religious networks helped to develop Danzigs literary culture. A new war broke out in 1409, culminating in the 