Duchy of Schleswig-Holstein-Hadersleben

In 1544, Holstein and Schleswig, both part of Danish Germany, were partitioned between the King (who remained sovereign over the entire territory and who retained the title of Duke of Holstein) and his two half-brothers, who received the spin-off (and nonsovereign) Duchies of Schleswig-Holstein-Hadersleben and Schleswig-Holstein-Gottorp. Although Hadersleben was located in Schleswig, its Holstein territories were administered from there, so I use the simplified country name of Holstein-Hadersleben. (Schleswig was outside of the Holy Roman Empire and therefore is not considered here in any detail.)

 

In 1580, the Hadersleben line died out and the following year its Holstein territory was split between the core Duchy of Holstein-Segeberg (Stadt and Amt Rendsburg and the southern half of Mitteldithmarschen) and Holstein-Gottorp (Amt Bordesholm and the northern half of Mitteldithmarschen). (Its Schleswig territories were similarly divided.)