The sixth German duchy, split from Bavaria in 976 as the first imperial state created after the original stem duchies; ruled in turn by Luitpoldings, Eppensteins, Sponheims and the counts of Gorizia-Tyrol before Louis the Bavarian granted it to the Habsburgs in 1335.
Bestowed on the dukes of Austria in 1335 by Emperor Louis IV after Henry of Gorizia-Tyrol died without male heirs, and thereafter a Habsburg hereditary land within Inner Austria; it remained a State of the Holy Roman Empire until the Empire's dissolution in 1806 and continued as an Austrian crown land until 1918.
The Land Between: A History of SloveniaOto Luthar (ed.) · 2008
The only accessible English-language history that treats the Carantanian-Carinthian ducal succession and the Slovene southern half of the duchy in depth, including the Duke's Chair investiture rite at Zollfeld.
A history of the Habsburg Empire, 1273-1700Jean Berenger · 1994
Covers the 1335 acquisition and Carinthia's place among the hereditary lands; used for the Habsburg phase, not as a general filler.