Trade was, in fact, thought of as a kind of war, for seventeenth century economists believed that, just as there was only so much gold and silver in the world, there could be only so much trade. Gustavus Adolphus, king of Sweden kept Swedish policy firmly focused on achieving imperialist expansion throughout the ups and downs of the Thirty Years War. When Sweden entered the Thirty Years War, the bellicose tendencies of the whole region became more central to the diplomatic affairs of western and southern Europe as well. One previously obscure territory was forged by the continuing wars into the main point of connection between the northeast and the rest of Europe: Brandenburg Prussia. Frederick William aided Emperor Leopold I in his fight against France in the War of the Spanish Succession and was rewarded with the title of King instead of Elector in 1701.