[2] Following the death of the ruler of the Duchy of Rawa, Siemowit II of Masovia, on 18 February 1345, Bolesław III of Płock had inherited from him lands of Sochaczew, Gostynin and Wizna.

In December 1381, following the death of his father, Siemowit IV had inherited Wizna Land reestablishing the state.

On 2 December 1382, he had pledged the lands of the duchy to the State of the Teutonic Order in exchange of 7 000 grzywnas.

In November 138 Siemowit IV had longed the period of the pledge in the exchange for 60 000 Prague groschen.

Despite that, Siemowit IV had continued to title himself the Duke of Wizna, while his brother remained from developing the administration and investing in the territory until 1410.