Christian II, 1481–1559, king of Denmark and Norway (1513–23) and Sweden (1520–23), son and successor of King John. After several unsuccessful attempts, he asserted claim to Sweden by force. However, his wholesale massacre of Swedish nobles at Stockholm (1520) alienated the Swedes, who raised Gustavus Vasa to the throne as Gustavus I, thus ending the Kalmar Union. In Denmark, Christian earned the hatred of the nobles and high clergy by thorough reforms in favor of the lower and middle classes, by inviting Lutheran preachers to Copenhagen, and by placing Sigbrit, mother of his Dutch mistress, in charge of the finances of the realm. In 1523 the nobles rebelled (particularly in Jutland), deposed Christian, and chose his uncle, Frederick I, as king. Christian fled, but in 1532 he was captured while attempting to recover the throne. He was imprisoned until his death. A gifted and educated ruler despite his despotic methods, Christian II did much to advance learning in Denmark.