Kammala jumla mai zuwa: Bayan mutuwar Boleslaus Yuriy na Masovia da Halych a 1340, an ba da haƙƙin mallakarsa ga danginsa Piast da dan uwansa, sarki Casimir III na Poland. Manyan mazauna yankin sun zabi daya daga cikin nasu, Dmytro Dedko, a matsayin mai mulki, kuma sun kori mamayewar Poland a lokacin
yaƙe-yaƙe game da maye gurbin Galicia-Volhynia Principality lokacin da Sarki Casimir III ya yi yaƙin neman zaɓe don cinye Lviv a 1340, yana ƙone tsohuwar gidan sarauta.