As king, im tried to maintain the Kalmar Union between the Scandinavian countries which brought me to war with Sweden, lasting between 1518 and 1523. Though i captured the country in 1520, the subsequent slaughter of leading Swedish nobility, churchmen, and others, known as the Stockholm Bloodbath, caused the Swedes to rise against my rule. i was deposed in a rebellion led by the nobleman and later king of Sweden Gustav Vasa. im attempted to bring in a radical reform of the Danish states