In 1434, Karl became a member of the
Privy Council of Sweden and in October of the same year he assumed one of its most senior offices,
Lord High Constable of Sweden, or
Riksmarsk. Because of the growing dissatisfaction among the
Swedish nobility with their king,
Erik of Pomerania, Karl was in 1436 made
Rikshövitsman, an office equating to Military Governor of the
Realm, and finally replaced the king as an elected regent from 1438 to 1440, as the result of the rebellion by
Engelbrekt Engelbrektsson. During Karl's brief regentship, the so-called Rebellion of David (a peasant rebellion) took place in Finland. Erik was forced to step down from the throne, and in 1440,
Christopher of Bavaria was elected king of Sweden, Norway and Denmark. At the coronation of Christopher in September 1441, Karl was dubbed a knight and appointed
Lord High Justiciar of Sweden, or
Riksdrots. In October he resigned as Lord High Justiciar and resumed his office as Lord High Constable. From 1442, he was the military governor,
hövitsman, at
Viborg in Finland (
Fief of Viborg). Karl acquired extensive fiefs, for example in Western Finland. His first seat was in Turku. Soon, Christopher's government began to take back fiefs and positions and he was forced to give up the
castle of Turku. Karl's next seat was the
castle of Viborg, on Finland's eastern border, where he kept an independent court, taking no heed of Christopher and exercising his own foreign policy in relation to such powers in the region as the
Hanseatic League, the Russian city of
Novgorod and the
Teutonic Knights in what are today Estonia and Latvia. ==King of Sweden and Norway==