adjusted to reflect an ability to pay. Crown tax revenues increased, but more importantly, the new system was perceived as fairer and more acceptable. A war with Luebeck in 1535 resulted in the expulsion of the Hanseatic traders, who previously had had a monopoly of foreign trade. With its own businessmen in charge, Sweden's economic strength grew rapidly, and by 1544 Gustavus controlled 60% of the farmlands in all of Sweden. Sweden now built the first modern army in Europe, supported by a sophisticated tax system and government bureaucracy. Gustavus proclaimed the Swedish crown hereditary and the house of Vasa ruled Sweden (1523–1654) and Poland (1587–1668). Early Modern Sweden During the 16th and 17th centuries, the kings demanded ever increasing taxes and military conscription, emphasizing the need for defense. However the money and manpower were used for offensive warfare. Indeed, when there seemed to be a real threat of invasion in 1655–1660, King Charles X Gustav asked the people to give more and to manage their own defences. Finally a balance was reached that provided a well supplied aggressive foreign policy. During the 17th century, after winning wars against Denmark, Russia, and Poland, Sweden (with scarcely more than 1 million inhabitants) emerged as a great power by taking direct control of the Baltic region, which was Europe's main source of grain, iron, copper, timber, tar, hemp, and furs. Sweden had first gained a foothold on territory outside its traditional provinces in 1561, when Estonia opted for vassalage to Sweden during the Livonian War. While, in 1590, Sweden had to cede Ingria and Kexholm to Russia, and Sigismund tried to incorporate Swedish Estonia into the Duchy of Livonia, Sweden gradually expanded at the eastern Baltic during the following years. In a series of Polish–Swedish War (1600–1629) and the Russo-Swedish Ingrian War, Gustavus Adolphus retook Ingria and Kexholm (formally ceded in the Treaty of Stolbovo, 1617) as well as the bulk of Livonia (formally ceded in the Treaty of Altmark, 1629). Sweden's role in the Thirty Years' War determined the political as well as the religious balance of power in Europe. From bridgeheads in Stralsund (1628) and Pomerania (1630), the Swedish army advanced to the south of the Holy Roman Empire, and in a side theater of the war deprived Denmark–Norway of Danish Estonia, Jämtland, Gotland, Halland, Härjedalen, Idre and Särna, became exempt from the Sound Dues, and established claims to Bremen-Verden,