Frederick I of Denmark and Norway (October 7, 1471 – April 10, 1533) was the son of the first Oldenburg King Christian I of Denmark, Norway and Sweden (1426–1481) and of Dorothea of Brandenburg (1430–1495). The name is also spelled Friedrich in German, Frederik in Danish, and Fredrik in Swedish and Norwegian.
The underage Frederick was elected co-Duke of Schleswig and Holstein in 1482, soon after the death of his father, the other co-duke being his ten years elder brother Johann (or Hans), the King. At Frederick's majority in 1490 both duchies were divided between the brothers.
In 1500 he'd convinced his brother and co-duke for a conquest of Dithmarschen, and a great army was called from not only the duchies, but with additions from all of the Kalmar Union for which his brother briefly was king. Also numerous German mercenaries took part. The expedition failed however miserably in the Battle of Hemmingstedt, where one third of all knights of Schleswig and Holstein lost their lives.
In 1523 his nephew Christian II, the King of Denmark, Norway and Sweden, was forced by disloyal nobles to abdicate, and the duke took the throne as king Frederick I. A group of Jutish nobles had offered Frederick the throne as early as 1513, when his brother king Hans died, but he had declined, rightly believing that the majority of the Danish nobility would be loyal to prince Christian.
It is not certain that Frederick ever learned to speak Danish. After becoming king, he continued spending most of his time at the castle of Gottorp in Schleswig.
During his rule as a Danish king Frederick had to suppress social revolts among the peasants at the same time as the rise of the Protestant movement made a balancing attitude a necessity. Without being a man of greater statesmanship Frederick managed to escape all open conflicts even though he seems to have accepted the spread of Lutheran propaganda. 1532 he succeeded in capturing Christian II who had tried to get a political come-back in Norway.
As King of Norway, Frederick is most remarkable in never having visited the country. He was never crowned King of Norway, and therefore styled himself King of Denmark, the Vends and the Goths, elected King of Norway.