Bohemia is the westernmost and largest historical region of the Czech lands in the present-day Czech Republic. In a broader meaning, Bohemia sometimes refers to the entire Czech territory, including Moravia and Czech Silesia, especially in a historical context, such as the Lands of the Bohemian Crown ruled by Bohemian kings.  Bohemia was a duchy of Great Moravia, later an independent principality, a kingdom in the Holy Roman Empire, and subsequently a part of the Habsburg Monarchy and the Austrian Empire. After World War I and the establishment of an independent Czechoslovak state, Bohemia became a part of Czechoslovakia. Between 1938 and 1945, border regions with sizeable German-speaking minorities of all three Czech lands were joined to Nazi Germany as the Sudetenland.