Graz is centrally located within today's "Bundesland" (state) of Styria, or "Steiermark" in German. "Mark" is an old German word indicating a large area of land used as a defensive border, in which the peasantry is taught how to organize and fight in the case of an invasion. With a strategic location at the head of the open and fertile Mur valley, Graz was historically a target of invaders, such as the Hungarians under Matthias Corvinus in 1481, and the Ottoman Turks in 1529 and 1532. Apart from the Riegersburg Castle, the Schlossberg was the only fortification in the region that never fell to the Ottoman Turks. Graz is home to the region's provincial armory, which is the world's largest historical collection of late medieval and Renaissance weaponry. It has been preserved since 1551, and displays over 30,000 items.