A younger son of King Christian I, he received the duchies of
        Schleswig and Holstein in 1490 when his elder brother became king of 
        Denmark. He failed when he tried to obtain sovereignty over parts of 
        Norway and Denmark after which he settled in Gottorp, where he 
        reformed the territory's administration. However, he remained hostile 
        to his brother and, when his brother died in 1513, to his nephew King 
        Christian II. In 1522 the nobles from Jutland rebelled against 
        Christian II and offered the Danish crown to Fredrik. He accepted and 
        was crowned the following year. In 1524 he was also accepted as king 
        of Norway. 
            At first he agreed to fight the Lutheran heresy but increasingly 
        supported them, to the point where he appointed Hans Tavsen as his 
        chaplain. His pro-Lutheran policy, increasing his popularity amongst 
        the lower classes, was probably designed to increase royal power at 
        the expense of the Danish church. 
            However, he retained the support of the state council when, in 
        1531 with the aid of Emperor Charles V, the deposed King Christian II 
        invaded Norway. Fredrik I imprisoned Christian II and, reaching 
        adiplomatic settlement with Emperor Charles V, maintained peace until 
        he died

Source: Leo van de Pas