Duchy of Thuringia

The Duchy of Thuringia, later known as the Landgraviate of Thuringia, was a polity in medieval Thuringia, initially a duchy, and then a landgraviate. It was centered in the homeland of Thuringians, encompassing territories previously ruled by independent Kings of Thuringia. During the first half of the 6th century, Thuringia came under the supreme rule of Frankish kings, and was organized as an eastern frontier region of the Merovingian kingdom of Austrasia. It was established as a duchy about 631, by King Dagobert I, who appointed a local Thuringian noble Radulf as the first Duke of Thuringia. It was recreated within the Carolingian Empire, and then belonged to the East Frankish Realm.

Within the Holy Roman Empire, the territory was initially divided into several counties, held by various noble families, among whom the Ludovingians emerged as the most powerful. Since 1131, they ruled as Landgraves of Thuringia and Princes of the Holy Roman Empire. Besides the landgravian domains, several minor counties also continued to exist throughout Thuringia, thus reflecting the feudal fragmentation of the land. Further divisions and occasional conflicts within dynasties who held the landgravian domains also contributed to that process, particularly since Ludovingians died out in 1247, and the Thuringian Landgraviate passed to Wettins, who already held the neighboring March of Meissen, and later acquired the Electorate of Saxony (1423). When William III, Landgrave of Thuringia died in 1482, his domains and titles passed to his nephews, Prince-Elector Ernest of Saxony and Duke Albert III of Saxony, who concluded the Treaty of Leipzig (1485) and divided all Wettinian domains, including those in Thuringia, with both sides continuing to use the Thuringian landgravian title, that was kept in dyastic traditions of both Ernestine and Albertine branches, as one of their secondary titles.