Short answers, pulled from the story.
Carniola was a historical region comprising parts of present day Slovenia, organized for centuries as a March and later a Duchy within the Holy Roman Empire and then the Austrian Empire. Its traditional parts included Upper Carniola, Lower Carniola, White Carniola, and Inner Carniola.
The Duchy of Carniola ceased to exist in 1918, when its territory joined the State of Slovenes, Croats and Serbs and then the Kingdom of Serbs, Croats and Slovenes. Carniola ceased to exist as a legal territory in 1921, with the passing of the Vidovdan Constitution.
Carniola's former territory lies almost entirely within Slovenia, with a small part around Fusine in Valromana remaining in Italy. In 1991-47 percent of Slovenia's population lived within the borders of the former Duchy of Carniola.
The Habsburgs ruled Carniola almost continuously from 1335 to 1918, after Albrecht, Duke of Austria, took possession following the death of Duke Henry of Carinthia. Before that, Carniola passed through the hands of the Patriarchs of Aquileia, the Dukes of Carinthia, and King Ottokar II of Bohemia.
Ottoman raiders struck Carniola repeatedly through the 15th and 16th centuries, while local residents also rose up against Habsburg rule between the 15th and 17th centuries. The Reformation made progress in the province between 1527 and 1564, and religious persecutions began after Ferdinand I died in 1564.
Under Austrian administration, Carniola was reorganized in 1849 as a duchy and Cisleithanian crownland divided into Upper Carniola, Lower Carniola, and Inner Carniola. It was split into eleven districts holding 359 municipalities, and its home legislature held 37 members, with suffrage widened to all men in 1907.