The Sverker dynasty continued in power until 1250, then giving way to the Folkungar line of kings. A century later, under the rule of Magnus Smek, a revolution occurred which set upon the throne Count Albrecht, of Mecklenburg, nephew of the deposed Magnus. This did not bring peace or quiet, and upon the invitation of one of the contending factions, Margaret, Queen of Denmark and Norway, invaded the country and captured the Swedish throne. She was succeeded by her nephew, Erik of Pomerania, who married Philippa, daughter of Henry the Fourth of England. Erik proved utterly incapable of managing the three kingdoms his aunt had united, and after a quarter of a century of civil war lost the allegiance of each of the three. Denmark and Norway chose for their ruler Erik’s nephew, Christopher of Bavaria, and Sweden was induced to ratify their choice. Upon his death, in 1448, the Oldenburg line, in Norway and Denmark, begins with Christian I. This king attempted to subjugate Sweden, but Karl Knudson, her marshal king, succeeded in keeping his crown. After his death, Hans, son and successor to Christian I., won Sweden by the aid of German mercenary troops. Again Sweden shakes off the Danish yoke, and again is subjugated by Christian II. At length in 1523 Gustaf I., known commonly in history by the title of Gustavus Vasa, liberated Sweden forever from foreign domination. But foreign domination was scarcely worse than the domestic tyranny of the nobles and the clergy. Gustaf set himself the task of breaking down this also. In his twenty-seven years of rule he established the reformed or Lutheran faith, elevated the peasantry, developed the resources of the country, replenished the national treasury and created a navy and army of defence.