 The accession of a new Danish–Icelandic Act of Union in late 1918 redefined Iceland, a longtime part of the Danish realm, as a sovereign state in a personal union with the King of Denmark.This made Christian the king of the mostly autonomous Kingdom of Iceland in addition to being King of Denmark.Christian (whose name in Iceland was officially "Kristján X") was the first and only monarch to ever reign over Iceland as a sovereign kingdom as opposed to ruling it as a province of a larger kingdom.