Not necessarily a kingdom can also be for example a vassal of another kingdom Look at the Habsburg Kingdom of Croatia it was definitely not in a personal union with the Habsburg Monarchy Or the Kingdom of Croatia Slavonia it was officialy Politi ki narod sa zasebnim teritorijem as specified in the Croatian Hungarian settlement If renaming this article to Kingdom of Croatia would endorse the personal union then a merge with the KoC 925 1102 would do the same Its not that I m totally against such a move the Kingdom of Hungary although they have special articles for various periods of it and Kingdom of Bohemia did the same thing but all the way to 1918 However Kingdom of Poland has only separate articles Bulgaria has two articles about the Bulgarian Empire and one stub article about both of them