The Duchy of Carinthia was a duchy located in southern Austria and parts of northern Slovenia. It was separated from the Duchy of Bavaria in 976, and was the first newly created Imperial State after the original German stem duchies. Carinthia remained a State of the Holy Roman Empire until its dissolution in 1806, a constituent part of the Habsburg Monarchy and of the Austrian Empire, it remained a Cisleithanian crown land of Austria-Hungary until 1918. By the Carinthian Plebiscite in October 1920, the area of the duchy formed the Austrian state of Carinthia. In the seventh century the area was part of the Slavic principality of Carantania, the Bavarian stem duchy was incorporated into the Carolingian Empire when Charlemagne deposed Odilos son Duke Tassilo III in 788. In the 843 partition by the Treaty of Verdun, Carinthia became part of East Francia under King Louis the German, after Berthold became Duke of Bavaria in 938, both territories were ruled by him. Duke Henrys son Henry II the Quarreller from 974 onwards, revolted against his cousin Emperor Otto II, at the same time Emperor Otto II created a sixth duchy in addition to the original stem duchies, the new Duchy of Carinthia. He reverted the possession of the territories to the Luitpoldings, when he split Carinthia from the Bavarian lands, over the centuries, the name Carinthia gradually replaced former Carantania. The realm of the Carinthian dukes initially comprised a vast territory including the marches of Styria, Carniola and Istria, though Henry once again managed to regain the ducal title in 985, Carinthia upon his death in 989 fell back to the Imperial Ottonian dynasty in Bavaria. Adalbero was removed from office in 1035 after he had out of favour with the Salian Emperor Conrad II. In 1039 Carinthia was inherited by Emperor Henry III himself, who split off the Carniolan march the following year and granted it to Margrave Poppo of Istria. In 1077, the duchy was given to Luitpold, again a member of the Eppensteiner family, upon his death the duchy was further reduced in area, a large part of the Eppenstein lands in what is today Upper Styria passed to Margrave Ottokar II of Styria. The remainder of Carinthia passed from Duke Henry III to his godchild Henry from the House of Sponheim, the most outstanding of the Spanheim dukes was Bernhard, the first Carinthian duke who was actually described and honoured in documents as prince of the land. The last Spanheim duke was Ulrich III, he signed a treaty with his brother Archbishop Philip of Salzburg. In spite of being supported by the Habsburg king Rudolf I of Germany, the duchy was seized by Rudolph and Philip died a year later in 1279. Rudolf, after being elected King of the Romans and defeating King Ottokar II, the Habsburgs would continue to rule Carinthia until 1918. As with the component parts of the Habsburg Monarchy, Carinthia remained a semi-autonomous state with its own constitutional structure for a long time. The Habsburgs divided up their territories within the family twice, according to the 1379 Treaty of Neuberg, each time, the Duchy of Carinthia became part of Inner Austria and was ruled jointly with the adjacent duchies of Styria and Carniola
Carinthia (yellow) within Inner Austria, c. 1790
Early 18th century map of Carinthia showing fiefs owned by Salzburg and Bamberg.