 Complete the following phrase:  On his return he led political negotiations with the Elector Augustus of Saxony and Frederick I of Prussia about the impending plans of war against Sweden. For much of Frederick IVs reign Denmark-Norway was engaged in the Great Northern War 17001721 against Sweden. In spite of the conclusion of the Peace of Travendal in 1700, there was soon a Swedish invasion and threats from Europes western naval powers. In 1709 Denmark again entered the war encouraged by the Swedish defeat at Poltava. Frederick IV commanded the Danish troops at the 