Until the Napoleonic Wars, Blankenhain had been a part of the Duchy of Saxe-Weimar. After the Fourth Coalition's defeat at Jena and Auerstedt, Napoleon attached the Lordship of Blankenhain to the Principality of Erfurt, directly subordinate to himself as an "imperial state domain" (), separate from the Confederation of the Rhine (nominally a French protectorate set up to replace the now-defunct Holy Roman Empire), which the surrounding Thuringian states had joined.