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 I, Duke of Cieszyn the Přemyslid dynasty in the person of Wenceslaus III, son and successor of Wenceslaus II. On 5 October 1305, Mieszko obtained his major victory when his daughter Viola Elisabeth married King Wenceslaus III. This union was a chance for Mieszko to make himself one of the most powerful figures in Bohemia, and he even began some attempts to obtain the Polish crown. However, Mieszko's promising career ended suddenly with the murder of Wenceslaus III (Olomouc, 4 August 1306). Viola Elisabeth never bore Wenceslaus III any children and the Přemyslid dynasty became extinct. After 1306 the political activity of Mieszko almost