It is very frequent that such local names are used internally or by other languages to denote a whole county or its official language. Examples: Anglia Poland from a Western Polish tribe, but Lengyelország [in Hungarian] from an Eastern Polish tribe. Magyar = one of the 7 conquering tribes. Moscow -> Muscovite [inEnglish], muszka [inHungarian]. Alemania [Sp.] from one of the German tribes.