<P> In the Middle Ages the regions situated on the mountainous border of the Duchy and the Kingdom of Bohemia had since the Migration Period been settled mainly by western Slavic Czechs . Along the Bohemian Forest in the west, the Czech lands bordered on the German Slavic tribes (German Sorbs) stem duchies of Bavaria and Franconia; marches of the medieval German kingdom had also been established in the adjacent Austrian lands south of the Bohemian - Moravian Highlands and the northern Meissen region beyond the Ore Mountains . In the course of the Ostsiedlung (settlement of the east) German settlement from the 13th century onwards continued to move into the Upper Lusatia region and the duchies of Silesia north of the Sudetes mountain range . </P> <P> From as early as the second half of the 13th century onwards these Bohemian border regions were settled by ethnic Germans, who were invited by the Přemyslid Bohemian kings--especially by Ottokar II (1253--1278) and Wenceslaus II (1278--1305). After the extinction of the Přemyslid dynasty in 1306, the Bohemian nobility backed John of Luxembourg as king against his rival Duke Henry of Carinthia . In 1322 King John of Bohemia acquired (for the third time) the formerly Imperial Egerland region in the west and was able to vassalize most of the Piast Silesian duchies, acknowledged by King Casimir III of Poland by the 1335 Treaty of Trentschin . His son, Bohemian King Charles IV, was elected King of the Romans in 1346 and crowned Holy Roman Emperor in 1355 . He added the Lusatias to the Lands of the Bohemian Crown, which then comprised large territories with a significant German population . </P> <P> In the hilly border regions German settlers established major manufactures of forest glass . The situation of the German population was aggravated by the Hussite Wars (1419--1434), though there were also some Germans among the Hussite insurgents . </P> <P> By then Germans largely settled the hilly Bohemian border regions as well as the cities of the lowlands; mainly people of Bavarian descent in the South Bohemian and South Moravian Region, in Brno, Jihlava, České Budějovice and the West Bohemian Plzeň Region; Franconian people in Žatec; Upper Saxons in adjacent North Bohemia, where the border with the Saxon Electorate was fixed by the 1459 Peace of Eger; Germanic Silesians in the adjacent Sudetes region with the County of Kladsko, in the Moravian--Silesian Region, in Svitavy and Olomouc . The city of Prague had a German - speaking majority from the last third of the 17th century until 1860, but after 1910 had the proportion of German speakers decreased to 6.7% of the population . </P>

Where was the sudetenland why was it important