“ But Boleslaus’s first Bohemian war proved unsuccessful, and was terminated by the marriage of his sister Swatawa with the Czech king Wratyslaus II. On the other hand Boleslaus’s ally, the fugitive Magyar prince Bela, succeeded with Polish assistance in winning the crown of Hungary. In the East Boleslaus was more successful. In 1069 he succeeded in placing Izaslaus on the throne of Kiev, thereby confirming Poland’s overlordship over Russia and enabling Boleslaus to chastise his other enemies, Bohemia among them, with the co-operation of his Russian auxiliaries. ”