Ottokar IV, of the Otakar dynasty, became Margrave of Styria in 1164 and Duke in 1180 when Styria became an independent duchy. He inherited vast estates and defended his borders against neighboring dukes and Hungary. Ottokar IV fortified his territories, rebuilding Graz and constructing the Fürstenfeld fortress. Leprosy-stricken and childless, he entered the Georgenberg Pact, agreeing to pass Styria to Leopold V of Austria. After his death in 1192, the joint rule of Styria and Austria began as per the agreement. Ottokar IV was initially buried at Žiče Charterhouse, later relocated to Rein Abbey in 1827.

Ottokar IV, Duke of Styria - Wikipedia