克里斯蒂安十世
In the event of one kingdom reaching independence from another but still under the same monarch, the monarch often retains the same number as he has already had in the older realm. King Christian X of Denmark thus became King Christian X of Iceland when Iceland became an independent kingdom in personal union with Denmark in 1918. The same is true for Commonwealth realms, where the monarch retains the regnal number from the British line of monarchs (see below).