Queen Elizabeth I of England ruled a kingdom. She identified her kingdom as being imperiled by the Zygons, and that Tenth Doctor had pledged himself to protect her kingdom. (TV: The Day of the Doctor)
In the Game of Napoleon and Wellington, the kingdom of England broke off from the United Kingdom, splitting from the separate kingdoms of Wales and Scotland. The Countess was aware that the United Kingdom was a nation which "started out as separate little kingdoms that gradually unified" and, upon the collapse of Napoleon's World Empire, they were encouraged by the Players to "revert to type". (PROSE: World Game)