 Complete the following phrase:  At the time of the Great Northern War, the northwest of the Holy Roman Empire was a patchwork with the Swedish dominion of Bremen-Verden located between the largely autonomous cities of Bremen and Hamburg, bordered to the south by the Electorate of Hanover, whose prince-elector George Louis became king of Great Britain in 1714, and to the north by the Duchy of Holstein, divided into Holstein-Glückstadt, ruled by the Danish king, and Holstein-Gottorp, whose duke Charles Frederick, a cousin and ally of Charles XII of Sweden, resided in Stockholm while Danish forces had occupied his share of the duchy only disturbed by Stenbocks march 