Christian II (1481-1559) was one of the most unpopular Danish kings and was eventually overthrown and imprisoned for life.

Christian II was born at Nyborg Castle in 1481 and was the son of King Hans and Queen Christina of Saxony. Christian II was the king of Denmark and Norway from 1513. He would rule these two countries until he was deposed in 1523. He briefly ruled Sweden from 1520-1521.

In 1507, Christian II met the Dutch merchants daughter Dyveke Sigbritsdatter in Norway, fell in love with her and took her back to Copenhagen as his mistress. In 1515 he married Isabella of Austria, the sister of the Holy Roman Emperor Charles V. Christian II did not give up Dyveke as his mistress even when ordered to do so by Charles in 1516. The following year Dyveke died after eating poisoned cherries.

The blame for Dyveke's death fell on a popular nobleman named Torben Oxe. Even though the Rigsråd, the Royal Council, found him innocent, Christian II had him retried and executed. This alienated the Rigsråd and the nobles in the Kingdom, as did the appointment of Dyveke's mother as Minister of Finance along with a mainly middle-class privy council.

In 1520 Christian II invaded Sweden and defeated and killed his archrival Sten Sture the Younger at the Battle of Bogesund. Sten Sture's widow Christina Gyllenstierna held out in Stockholm for some months before she surrended to Christian II. In November, Christian II was crowned King of Sweden in Stockholm. However, he then sent Christina Gyllenstierna to imprisonment in the Blåtårn in Copenhagen Castle and had Sten Sture's body exhumed and burnt. Christian II then ordered the massacre of 82 Swedish nobles and bishops. For this, Christian II is still remembered in Sweden as Christian the Tyrant and the massacre is known as the "Stockholm Bloodbath". 

In 1521, Sweden rose up against him and by 1523, tired of his excessive taxation, so did Jutland and Christian II's uncle, Frederick of Holstein. He was later proclaimed King Frederick II. Christian II fled to the Netherlands and lived there in exile until he tried to reclaim the throne again in 1531. He was defeated and spent the rest of his life in captivity, first in Sønderborg Castle and finally in Kalundborg Castle. Christian II is buried in Odense, Saint Canute's Cathedral.