Christian I of Denmark (1426 – 1481), Danish monarch and union king of Denmark (1448 – 1481), Norway (1450 – 1481) and Sweden (1457 – 1464), under the Kalmar Union. In Sweden his short tenure as regent was preceded by viceroys, Jöns Bengtsson Oxenstierna and Erik Axelsson Tott and succeeded by viceroy Kettil Karlsson Vasa.

He was born in February 1426 in Oldenburg. His father was Count Dietrich of Oldenburg (died 1444). His mother was his father's second wife, Hedwig of Schleswig and Holstein (died 1436). Christian had two brothers, Count Moritz V of Delmenhorst (1428 - 1464) and Count Gerhard VI of Oldenburg and Delmenhorst (1430 - 1500), and one sister Adelheid.

Christian married Dorothea of Brandenburg (1430 - November 25 1495), the widow of King Christopher of Bavaria and thus dowager queen, on October 28 1449 in Copenhagen. Dorothea and Christian had five children:

1. Olaf (1450-1451)
2. Knut (1451-1455)
3. John (Kung Hans) (1455 - 1513), Duke of Schleswig and Holstein, King of Denmark, Norway and Sweden
4. Margarete of Denmark (1456-1486), 13 years old married to the 17 years old King James III of Scotland
5. Frederick (1471-1533), Duke of Schleswig and Holstein, King of Denmark and Norway

King Christian died in Copenhagen on May 21, 1481, at the age of 55. Through his fourth and fifth children respectively, he was an ancestor to James VI, of Scotland and England, and his wife, Anne of Denmark. He is therefore an ancestor to the present-day British royal family, including Elizabeth II, Queen of Great Britain and Northern Ireland.