Some of the fortresses built by Ottokar were for centuries the strongest in Bohemia. Ironically, Bezděz Castle served as a prison for his son Wenceslaus II of Bohemia for short time after Ottokar's death. The castle housed Bohemian legal records Zemské desky and many spiritual and temporal treasures during the destructive civil strife of the Hussite wars (1419–1434) in Bohemia. It was conquered in 1620, during the 30 Years' War, but by then it was long deserted, and in that state was defended by rebelling subjects against an Imperial army. Before his conflict with Rudolf of Habsburg, Ottokar exacted influence over a number of relatives, allies and vassals in Germany, such as the Margraviate of Brandenburg — and spiritual principalities, including the Archbishopric of Salzburg and the Patriarchate of Aquileia. After the death of Konradin in 1268 he was an heir of the House of Hohenstaufen's claim to the imperial crown. However, he did not raise this claim, remaining content with informal influence in Germany. In 1267 he was appointed protector of the royal domains (of the Holy Roman Empire) east of the Rhine by the German king, Richard of Cornwall. He held this office till 1273. Ottokar is a significant figure in history and legend. In the "Divine Comedy" by Dante, Ottokar is seen outside the gates of Purgatory, in amiable companionship with his imperial rival Rudolf. He is also the protagonist of a tragedy by the 19th-century Austrian playwright Franz Grillparzer, titled "König Ottokars Glück und Ende". There is a statue dedicated to him.