Re: Democratic Republics in Fantasy Worlds?
Dittmarsch, Ditmarsch, Dithmarsch are all orthographic possibilities for contemporary German. Adding the "en" at the end either pluralises it or (I think, cuz I'm too lazy to look up my list of case endings) can be a genitive that's been incorporated in the word by traditional usage. I take it as the latter, having had more than one argument over endings in weird 17th century German names and placenames.
Wikipedia cites it in a crapulous article on "village communities" lifted from the 11th ed. of the Encyclopaedia Brittanica, but, oddly enough, omits the actual article, s.v. Dithmarschen. "A territory between the Eider, Elbe and the North Sea, forming the western part of the old ducy of Holstein.... about 550 sq miles including 90,000 inhabitants [in 1909]," all coastal marshland, some of which was reclaimed, some not.
Like many similar communities its independence was rooted in the competing claims of local potentates like the Archbishop of Bremen and his rival, the King of Denmark. The territory was divided into four "Marks" and governed by a Landrat of 48 elective "consuls." Dittmarsch defeated several invasions by the Duke of Holstein [politics in this corner of Europe are nothing if not complicated] during the early 1500s --cue heroic peasants waging guerilla war from their marshy fastness-- before sad reality triumphed.