Mieszko I of Poland and half a century later, by Bishop Thietmar of Merseburg. By the time Mieszko I took over from his father, the Polans' tribal federation of Greater Poland had for some time been actively expanding. Continuing this process, perhaps in the first years of Mieszko's reign, if it had not been done already by his father, Mieszko I conquered Masovia. Likely also during that period or earlier, at least partially Gdańsk Pomerania was obtained. Mieszko's interests were then concentrated mainly on areas occupied by the eastern (near the Oder River) branches of the Polabian Slavs; some of them became soon subordinated
Mieszko II Lambert to Hungary because during his travel he was stopped by Rus' troops. King Stephen I of Hungary wasn't favorable to accepting him in his country. Without alternatives, Mieszko II went to Bohemia. Duke Oldřich once again imprisoned him. This time the King wasn't counting with the Imperial support. Mieszko II was not only imprisoned but also castrated, which was to be a punishment to Bolesław I the Brave, who blinded Duke Boleslaus III the Red (Oldřich's brother) thirty years before. Mieszko II and his wife never reunited again; according to some sources they were either officially divorced or only separated.