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.[37] 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. The Ottoman army battling the Habsburgs in present-day Slovenia during the Great Turkish War 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.[37] Early modern period[edit] After the dissolution of the Republic of Venice in 1797, the Venetian Slovenia was passed to the Austrian Empire. The Slovene Lands were part of the French-administered Illyrian Provinces established by Napoleon, the Austrian Empire and Austria-Hungary. Slovenes inhabited most of Carniola, the southern part of the duchies of Carinthia and Styria, the northern and eastern areas of the Austrian Littoral, as well as Prekmurje in the Kingdom of Hungary.[38] Industrialization was accompanied by construction of railroads to link cities and markets, but the urbanization was limited. Due to limited opportunities, between 1880 and 1910 there was extensive emigration; around 300,000 Slovenes (1 in 6) emigrated to other countries,[39] mostly to the US, but also to South America (the main part to Argentina), Germany, Egypt, and to larger cities in Austria-Hungary, especially Vienna and Graz. Despite this emigration, the population of Slovenia increased significantly.[39] Literacy was exceptionally high, at 80–90%.[39] The 19th century also saw a revival of culture in Slovene, accompanied by a Romantic nationalist quest for cultural and political autonomy. The idea of a United Slovenia, first advanced during the revolutions of 1848, became the common platform of most Slovenian parties and political movements in Austria-Hungary. During the same period, Yugoslavism, an ideology stressing the unity of all South Slavic peoples, spread as a reaction to Pan-German nationalism and Italian irredentism. World War I[edit] See also: Italian front (World War I), Battles of the Isonzo, Treaty of London (1915), and Corfu Declaration The Battles of the Isonzo took place mostly in rugged mountainous areas above the Soča River. World War I brought heavy casualties to Slovenes, particularly the twelve Battles of the Isonzo, which took place in present-day Slovenia's western border area with Italy. Hundreds of thousands of Slovene conscripts were drafted into the Austro-Hungarian Army, and over 30,000 of them died. Hundreds of thousands of Slovenes from Princely County of Gorizia and Gradisca were resettled in refugee camps in Italy and Austria. While the refugees in Austria received decent treatment, the Slovene refugees in Italian camps were treated as state enemies, and several thousand died of malnutrition and diseases between 1915 and 1918.[40] Entire areas of the Slovene Littoral were destroyed. The Treaty of Rapallo of 1920 left approximately 327,000 out of the total population of 1.3 million Slovenes in Italy.[41][42] After the fascists took power in Italy, they were subjected to a policy of violent Fascist Italianization. This caused the mass emigration of Slovenes, especially the middle class, from the Slovene Littoral and Trieste to Yugoslavia and South America. Those who remained organized several connected networks of both passive and armed resistance. The best known was the militant anti-fascist organization TIGR, formed in 1927 to fight Fascist oppression of the Slovene and Croat populations in the Julian March.[43][44] Kingdom of Serbs, Croats, and Slovenes (later the Kingdom of Yugoslavia)[edit] See also: Creation of Yugoslavia, Carinthian Plebiscite, and Rudolf Maister The proclamation of the State of Slovenes, Croats and Serbs at Congress Square in Ljubljana on 29 October 1918 The Slovene People's Party launched a movement for self-determination, demanding the creation of a semi-independent South Slavic state under Habsburg rule. The proposal was picked up by most Slovene parties, and a mass mobilization of S