Rubuta ci gaba don wannan sakin layi - Bayan Boleslaus Yuriy na Masovia da Halych mutuwar a 1340, da hakkin ya yankin da aka wuce zuwa ga 'yan'uwansa Piast daular da dan uwan, 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 kan gadon mulkin Galicia-Volhynia Principality
lokacin da Sarki Casimir III ya yi yaƙin neman zaɓe don cinye Lviv a 1340, yana ƙone tsohon gidan sarauta.