▁El be ▁river . ▁Later ▁named ▁Al bre chts burg , ▁the ▁castle ▁about ▁ 9 6 5 ▁became ▁the ▁seat ▁of ▁the ▁Me issen ▁marg ra ves , ▁installed ▁by ▁Emperor ▁Otto ▁I ▁when ▁the ▁vast ▁Mar ca ▁Ger on is ▁( G ero ' s ▁march ) ▁was ▁partition ed ▁into ▁five ▁new ▁marg ra vi ates , ▁including ▁ ▁Me issen , ▁the ▁Sax on ▁Eastern ▁March , ▁and ▁also ▁the ▁Northern ▁March ▁which ▁eventually ▁became ▁the ▁Mar gra vi ate ▁of ▁Brandenburg . ▁▁ ▁During ▁the ▁t enth ▁century , ▁the ▁Me issen ▁marg ra ves ▁tempor arily ▁extended ▁their ▁territory ▁into ▁the ▁Mil cen i ▁lands ▁up ▁to ▁the ▁K w isa ▁( Que is ) ▁river ▁and ▁the ▁border ▁with ▁the ▁S iles ian ▁region ▁of ▁the ▁Early ▁Polish ▁state . ▁The ▁eastern ▁lands ▁around ▁B aut zen ▁( B ud iss in ), ▁later ▁known ▁as ▁Upper ▁L us atia , ▁were ▁c eded ▁to ▁the ▁Polish ▁du ke ▁B oles ław ▁I ▁the ▁Bra ve ▁according ▁to ▁the ▁ 1 0 1 8 ▁Peace ▁of ▁B aut zen ; ▁in ▁ 1 0 7 6 ▁they ▁passed ▁to ▁the ▁Duke ▁of ▁Boh emia ▁as ▁an ▁Imperial ▁f ief . ▁▁ ▁From ▁ 1 0 8 9 , ▁the ▁Me issen ▁marg rav ial ▁title ▁became ▁the ▁honor ▁of ▁the ▁Sax on ▁House ▁of ▁W ett in ▁and ▁remained ▁as ▁the ▁dynast y ' s ▁possession ▁ever ▁since . ▁In ▁the ▁ 1 3 th ▁century