▁power . ▁Ö z ▁Beg ▁also ▁launched ▁military ▁exped itions ▁into ▁Lith u ania , ▁as ▁it ▁was ▁clear ▁that ▁it ▁threatened ▁Mong ol ▁domin ance ▁in ▁Russia . ▁ ▁Rel ations hip ▁with ▁Ruth en ian ▁princes ▁ ▁After ▁Ö z ▁Beg ' s ▁army ▁killed ▁Lev ▁II ▁and ▁his ▁brother ▁And rey ▁( co - k ings ▁of ▁Gal icia - Vol h yn ia , ▁and ▁last ▁of ▁the ▁R ur ik id ▁D ynast y ) ▁in ▁ 1 3 2 3 , ▁the ▁Grand ▁Duch y ▁of ▁Lith u ania ▁and ▁the ▁Kingdom ▁of ▁Poland ▁had ▁access ▁to ▁control ▁over ▁Gal icia - Vol h yn ia . ▁The ▁Lith u ani ans ▁defeated ▁the ▁Rus ' ▁boy ars ▁and ▁occupied ▁K iev ▁and ▁its ▁surrounding ▁areas . ▁In ▁ 1 3 3 7 , ▁the ▁joint ▁Russian ▁and ▁Hor de ▁army ▁pen etr ated ▁to ▁Lub lin . ▁At ▁the ▁request ▁of ▁the ▁Gal ician ▁no blem an ▁D my t ro ▁D ed ko , ▁the ▁k han ▁sent ▁ 4 0 , 0 0 0 ▁caval ries ▁against ▁King ▁Cas imir ▁III , ▁which ▁was ▁divided ▁into ▁the ▁V ist ula . ▁ ▁Gene al ogy ▁G eng his ▁Khan ▁J och i ▁B atu ▁Khan ▁To q o q an ▁M engu - Tim ur ▁T og hr il cha ▁Ö z ▁Beg ▁ ▁Notes ▁ ▁References ▁ ▁At wood , ▁Christopher ▁P . ▁Encyclopedia ▁of ▁Mong olia ▁and ▁the ▁Mong ol ▁Empire .