Christian II of Denmark is deposed as king of Sweden and Gustav Vasa is elected regent.

Gustav I, born Gustav Eriksson of the Vasa noble family and later known as Gustav Vasa (12 May 1496 29 September 1560), was King of Sweden from 1523 until his death in 1560, previously self-recognised Protector of the Realm (Riksfrestndare) from 1521, during the ongoing Swedish War of Liberation against King Christian II of Denmark, Norway and Sweden. Gustav rose to lead the rebel movement following the Stockholm Bloodbath, where his father was executed. Gustav's election as king on 6 June 1523 and his triumphant entry into Stockholm eleven days later marked Sweden's final secession from the Kalmar Union.As king, Gustav proved an energetic administrator with a ruthless streak not inferior to his predecessor's, brutally suppressing subsequent uprisings (three in Dalarna which had once been the first region to support his claim to the throne one in Vstergtland, and one in Smland). He worked to raise taxes and bring about a Reformation in Sweden, replacing the prerogatives of local landowners, noblemen and clergy with centrally appointed governors and bishops. His 37-year rule, which was the longest of an adult Swedish king to that date (subsequently passed by Gustav V and Carl XVI Gustav) saw a complete break with not only the Danish - Norwegian supremacy but also the Roman Catholic Church, whose assets were nationalised, with the Lutheran Church of Sweden established under his personal control. He became the first truly autocratic native Swedish sovereign and was a skilled bureaucrat and propagandist, with tales of his largely fictitious adventures during the liberation struggle still widespread to this day. In 1544, he abolished Medieval Sweden's elective monarchy and replaced it with a hereditary monarchy under the House of Vasa, which held the Swedish throne until 1654. Three of his sons, Eric XIV, John III and Charles IX, held the kingship at different points.Gustav I has subsequently been labelled the founder of modern Sweden, and the "father of the nation". Gustav liked to compare himself to Moses, whom he believed to have also liberated his people and established a sovereign state. As a person, Gustav was known for ruthless methods and a bad temper, but also a fondness for music and had a certain sly wit and ability to outmaneuver and annihilate his opponents. He founded one of the oldest orchestras of the world, Kungliga Hovkapellet (Royal Court Orchestra); thus Royal housekeeping accounts from 1526 mention twelve musicians including wind players and a timpanist but no string players. Today Kungliga Hovkapellet is the orchestra of the Royal Swedish Opera.

Christian II (1 July 1481 – 25 January 1559) was a Scandinavian monarch under the Kalmar Union who reigned as King of Denmark and Norway, from 1513 until 1523, and Sweden from 1520 until 1521. From 1513 to 1523, he was concurrently Duke of Schleswig and Holstein in joint rule with his uncle Frederick.

As king, Christian tried to maintain the Kalmar Union between the Scandinavian countries which brought him to war with Sweden, lasting between 1518 and 1523. Though he 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 his rule. He was deposed in a rebellion led by the nobleman and later king of Sweden Gustav Vasa. He attempted to bring in a radical reform of the Danish state in 1521–22, which would have strengthened the rights of commoners at the expense of the nobles and clergy. The nobility rose against him in 1523, and he was exiled to the Netherlands, ceding the Danish throne to Frederick. After attempting to reclaim the thrones in 1531, he was arrested and held in captivity for the rest of his life, first in Sønderborg Castle and later at Kalundborg Castle. Supporters tried to restore him to power both during his exile and his imprisonment but they were defeated decisively during the Count's Feud in 1536. Christian died at Kalundborg in 1559.

Christian married Isabella of Austria, granddaughter of Maximilian I, Holy Roman Emperor, in 1515. Isabella died in 1526, after which her family took Christian's three children from him. His relationship with his mistress, Dyveke Sigbritsdatter, pre-dated his marriage and continued until her death in 1517. Christian's persecution of her supposed murderer contributed to his political isolation and downfall. Dyveke's mother, Sigbrit Willoms, became an influential councillor and followed Christian into exile.