Frederick II of Denmark (1534–1588), King of Denmark and Norway; Frederick III of Denmark (1609–1670), King of Denmark and Norway; Frederick IV of Denmark (1671–1730), King of Denmark and Norway; Frederick V of Denmark (1723–1766), King of Denmark and Norway; Frederick VI of Denmark (1768–1839), King of Denmark and Norway; Frederick ...
Just six years later, on 14 May 1912, King Frederick VIII died, and Frederick's father ascended the throne as King Christian X. Frederick himself became crown prince. On 1 December 1918, as the Danish–Icelandic Act of Union recognized Iceland as a fully sovereign state in personal union with Denmark through a common monarch , Frederick also became crown prince of Iceland (where his name was ...