Duchy of Bohemia and Early Kings
Duchy of Bohemia was a direct successor to Great Moravia and was originally ruled by the Premyslids , then in 1003 anti-duke Vladivoj asked for Bohemia from the Henry II, Holy Roman Emperor (so saying he owned it) and it became a part of the empire. In 1085 duke Vratislaus II was given the title of King after he served Henry IV, this crown was uninheritable and so his successor was again duke, his grandson Vladislav II was again given the title in 1158 for his service to Barbarossa, but again it was uninheritable.
In 1212 the emperor Frederick II finally gave Vladislav's son Premysl Otakar I an inheritable crown, however Premyslids didn't last very long, his great grandson Wenceslaus II took the titles King of Poland and King of Hungary, Hungary broke away in 1301 and his son Wenceslaus III was killed in 1306 during a march to reestablish his rule in Poland. This followed by 4 years of battle between two claimants (Henry I andRudolph I ), finally the tile went to John I . This made a new house the ruler (House of Luxembourg). But after the rule of Charles IV, his son Wenceslaus IV 's reign saw early Hussite rebellion which lasted throwout the reign of his brother Sigismund I , his son-in-law's Albrecht I' s reign and his son Ladislaus 's reign. Then the country went under interregnum and the lords elected the only Hussite king ever, George of Poděbrady. He decided that the younger sister of Ladislaus's son Vladislaus Jagellon would be the next king. Vladislaus II (II as king) died in 1516 and his son Louis became the ruler. At this time it de facto became a part of the Personal Union of Hungary and Bohemia.
Like Vladislav who ruled from Budapest Louis almost never showed up, his de facto right arms in Bohemia was Zdeněk of Rozmital, nephew of King George, who had a problem with Vilém of Pernštejn, that almost pushed Bohemia into a civil war. This didn't happen and in 1522 Louis tried to enforce his rule. He then made King George's grandson Charles of Munsterberg a placeholder. In 1526 after Louis almost died in the Battle of Mohac he decided to make sure his realm would stay in one piece. In 1533 he made a contract with the lords of both kingdoms. But nothing much was done afterwards as he had to battle a spreading Lutheranism in Hungary and later a second Turkish invasion.
Casimir I was more a Bohemian ruler, as he and his mother were pushed from Hungary after his father died in 1543, lords of Bohemia and lords Hungary made him king in the Cathedral on the Prague Castle. One of his first order of business was to asked his uncle Ferdinand of Spain to join him and his great-uncle Sigismund I in a defence against the Ottomans.