Frederick was for a time involved in coup plans in
Denmark-Norway. His wife Dorothea was eldest daughter of
Christian II of Denmark, the former King of Denmark, Norway and Sweden who was deposed after a Danish noble rebellion in 1523. The exiled Christian II was contacted by
Olav Engelbrektsson,
Catholic Archbishop of Norway and head of the
Council of the Realm, in 1529, about retaking the throne of Norway from the Protestant friendly King
Frederick I. Christian II was a Protestant, but was also the brother-in-law of
Emperor Charles V and therefore vowed to help the Catholic cause in Norway. Christian II tried to retake Norway in 1531, but he was defeated in 1532. He was then imprisoned and was kept a prisoner for the next 27 years in Denmark. After Frederick's marriage to Dorothea in 1535, Frederick soon sent a letter to Olav Engelbrektsson (via emissaries in
Brussels) telling him that he would claim the throne and he also promised military support from himself and Charles V. In the winter of 1536, Olav Engelbrektsson sent squads of supporters to villages in
Eastern Norway; among other things the squads read the letter out to people, signalling that a new ruler could be on his way. However, few peasants joined the would-be rebellion, but other sources say that many farmers and
bourgeoisie in Eastern Norway rose up in rebellion for the Archbishop, but it soon failed as no actual support from Frederick or Charles came. In the winter of 1537, then, Frederick did send two ships from the
Habsburg Netherlands. However, this was to no avail as the
King of Denmark mounted a naval offensive to secure Norway around the same time. Olav Engelbrektsson fled the country in April, bishops
Hoskuld Hoskuldsson and
Mogens Lauritssøn were arrested, in June, other supporters were punished and the Catholic Church in Norway and the Council of the Realm were abolished. Frederick and his wife Dorothea never gave up on his claim to the throne of Norway (and also Denmark), and worked actively to have the Emperor Charles V to support it. In 1539, they visited the Emperor in Spain to press the matter, but without success. In 1544, Frederick became Elector Palatine. The Emperor officially acknowledged Christian III as king of Denmark and Norway the same year, in the
Treaty of Speyer, but Frederick continued to press his claim until his death. == Prince-elector of the Electoral Palatinate ==