I have a database in which we track laws from several territories of the Roman-German Empire over several centuries. It seems that while there is surprisingly good coverage for the subject matter of the laws in the German "Gemeinsame Normdatei" (GND), the situation for historical political entities like duchies, counties etc. is much more difficult.
There are no normdata or even just Id's at the GND, and in most cases no entries in wikipedia (or if there are some, they are only sub-chapters in larger articles about a present-day entity). I have not checked in wikidata but I don't have much hope. An exchange with Michael Piotrowski from Lausanne resulted in a document XP Z 44-002 by the French norm authority, AFNOR, but that is quite biased and was at one point explicitly rejected from the ISO process (which Michael told me from the outset). Finally, while ISO 3661 is a set of standards for current political entities like "DE" for Germany, "US-VA" for Virgina etc., I have seen people use private areas that this standard provides like XV-TU at the recent LinkedPasts IV symposion. (I think it was the Ottoman Recogito project, but I am not 100% sure.)
Does anyone of you have an idea or even a workable approach to identifying these in more than just a project/private way?