Battle of

the Vistula River - April 7, 1340 years, died poisoned by the boyars Prince of Galicia-Volhynia, Boleslaw Jerzy Trojdenowicz. After the death without issue left his principalit y to drop Casimir the Great. Polish king acted quickly and alread y nine days after his death he Trojdenowicza journey to Russia. However, to fight for the principality of Galicia-Volhynia also starring Tatars, which had been allied to some Ruthenian boyars opposed the inclusion of Ruthenian lands to the crown.