In 1570, during the reign of John Frederick, Duke of Pomerania, a congress was held at Stettin ending the Northern Seven Years' War. During the war, Stettin had tended to side with Denmark, while Stralsund tended toward Swedenas a whole, however, the Duchy of Pomerania tried to maintain neutrality. Nevertheless, a Landtag that had met in Stettin in 1563 introduced a sixfold rise in real estate taxes to finance the raising of a mercenary army for the duchy's defence. Johann Friedrich also succeeded in elevating Stettin to one of only three places allowed to coin money in the Upper Saxon Circle of the Holy Roman Empire, the other two places being Leipzig and Berlin. Bogislaw XIV, who resided in Stettin beginning in 1620, became the sole ruler and Griffin duke when Philipp Julius, Duke of Pomerania died in 1625. Before the Thirty Years' War reached Pomerania, the city, as well as the entire duchy, declined economically due to the decrease in importance of the Hanseatic League and a conflict between Stettin and Frankfurt an der Oder.