information:filtering, structural:scholar_edition, linguistic:voice_change, structural:expansion, stylistic:style_transfer
Middle Ages

The Carantanians, one of the ancestral groups of the modern Slovenes, particularly the Carinthian Slovenes, were the first Slavic people to accept Christianity. They were mostly Christianized by Irish missionaries, among them Modestus, known as the "Apostle of Carantanians". This process, together with the Christianization of the Bavarians, was later described in the memorandum known as the Conversio Bagoariorum et Carantanorum, which is thought to have overemphasized the role of the Church of Salzburg in the Christianization process over similar efforts of the Patriarchate of Aquileia.

In the mid-8th century, Carantania became a vassal duchy under the rule of the Bavarians, who began spreading Christianity. Three decades later, the Carantanians were incorporated, together with the Bavarians, into the Carolingian Empire. During the same period Carniola, too, came under the Franks, and was Christianised from Aquileia. Following the anti-Frankish rebellion of Liudewit at the beginning of the 9th century, the Franks removed the Carantanian princes, replacing them with their own border dukes. Consequently, the Frankish feudal system reached the Slovene territory.

After the victory of Emperor Otto I over the Magyars in 955, Slovene territory was divided into a number of border regions of the Holy Roman Empire. Carantania was elevated into the Duchy of Carinthia in 976.

By the 11th century, the Germanization of what is now Lower Austria, effectively isolated the Slovene-inhabited territory from the other western Slavs, speeding up the development of the Slavs of Carantania and of Carniola into an independent Carantanian/Carniolans/Slovene ethnic group. By the High Middle Ages, the historic provinces of Carniola, Styria, Carinthia, Gorizia, Trieste, and Istria developed from the border regions and were incorporated into the medieval Holy Roman Empire. The consolidation and formation of these historical lands took place in a long period between the 11th and 14th centuries, and were led by a number of important feudal families, such as the Dukes of Spanheim, the Counts of Gorizia, the Counts of Celje, and, finally, the House of Habsburg. In a parallel process, an intensive Germanization significantly diminished the extent of Slovene-speaking areas. By the 15th century, the Slovene ethnic territory was reduced to its present size.

In 1335, Henry of Gorizia, Duke of Carinthia, Landgrave of Carniola and Count of Tyrol died without a male heir, his daughter Margaret was able to keep the County of Tyrol, while the Wittelsbach emperor Louis IV passed Carinthia and Carniolan march to the Habsburg duke Albert II of Austria, whose mother, Elisabeth of Carinthia is a sister of the late duke Henry of Gorizia. Therefore, most of the territory of present-day Slovenia became a hereditary land of the Habsburg monarchy. As with the other component parts of the Habsburg monarchy, Carinthia and Carniola remained a semi-autonomous state with its own constitutional structure for a long time. The counts of Celje, a feudal family from this area who in 1436 acquired the title of state princes, were Habsburgs ' powerful competitors for some time. This large dynasty, important at a European political level, had its seat in Slovene territory but died out in 1456. Its numerous large estates subsequently became the property of the Habsburgs, who retained control of the area right up until the beginning of the 20th century. Patria del Friuli ruled present western Slovenia until Venetian takeover in 1420.

At the end of the Middle Ages, the Slovene Lands suffered a serious economic and demographic setback because of the Turkish raids. In 1515, a peasant revolt spread across nearly the whole Slovene territory. In 1572 and 1573 the Croatian-Slovenian peasant revolt wrought havoc throughout the wider region. Such uprisings, which often met with bloody defeats, continued throughout the 17th century.