deeds of the respective towns. By supporting the city of Jihlava (German: Iglau) with its mines, he laid foundation of the silver wealth of later Bohemian kings. Privileges of civic charters usually excluded the towns from obedience to the traditional courts held by members of nobility. This can be seen as a step towards equality and a precursor of modern civil law. In the country, Ottokar's introduction of the Law of Emphyteusis into the Czech law is sometimes interpreted as "Germanization". In fact it was creative, for it freed subjects from feudal obligations, except for rent — and tax, if such was levied. Free selling and leaving of estates could also be bought and soon became common. Thus, Ottokar can be reckoned an early Bohemian ruler who furthered Bohemian rights in medieval times. This change of legal environment in Bohemia was introduced by systematic founding of villages chartered under this law. He issued also a general privilege to the Jews (1254), which established principles of integration of the Jews into the Czech society until 1848. The Jews were now eligible for various positions, such as servants of crown, thereby being somewhat less subject to discrimination. Instead of being able to claim only the support of individual lords, the Jews could from then on claim support of any royal officer. Ottokar followed with a systematic policy of strengthening his domains by building fortifications. Besides supporting towns, he built many fortresses himself — Zvíkov Castle, Křivoklát Castle or Bezděz Castle in Bohemia, and the famed Hofburg Palace in Vienna — and also induced his vassals to build castles. A sign of rising strength of Bohemia, it was also a reaction to the Mongol raids of the 13th century (see Béla IV of Hungary). Conflict for the title of ownership to these fortified places built by members of nobility was probably the source of an uprising in 1276, which cost Ottokar the Austrian lands, and two years later (in an attempt for reconquest) his life. 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