Christian X was King of Denmark from 1912 to 1947, and the only King of Iceland between 1918 and 1944.
He was a member of the House of Glücksburg, a branch of the House of Oldenburg, and the first monarch since King Frederick VII born into the Danish royal family; both his father and his grandfather were born as princes of a ducal family from Schleswig. Among his siblings was King Haakon VII of Norway. His son became Frederick IX of Denmark.
His character has been described as authoritarian and he strongly stressed the importance of royal dignity and power. His reluctance to fully embrace democracy resulted in the Easter Crisis of 1920, in which he dismissed the democratically elected Social Liberal cabinet with which he disagreed, and installed one of his own choosing. This was in accordance with the letter of the constitution, but the principle of parliamentarianism had been considered a constitutional custom since 1901.