, ▁probably ▁of ▁Roman ▁origin . ▁One ▁followed ▁the ▁river ▁É ser a ▁through ▁the ▁important ▁town ▁of ▁Gra us ▁south ▁to ▁Mon z ón ▁and ▁the ▁lower ▁reaches ▁of ▁the ▁river ▁Cin ca . ▁East ▁of ▁the ▁Cin ca ▁lay ▁the ▁other ▁route , ▁connecting ▁Bol ta ña ▁and ▁Barb astro . ▁The ▁Re con qu ista ▁of ▁the ▁Cin ca ▁valley ▁and ▁surrounding ▁territory ▁to ▁its ▁west ▁was ▁rapid . ▁By ▁ 1 0 4 9 ▁Per arr ú a ▁was ▁the ▁most ▁advanced ▁position ▁on ▁the ▁É ser a , ▁held ▁by ▁a ▁don ▁Sun iero , ▁and ▁by ▁ 1 0 6 2 ▁L agu ar res ▁was ▁the ▁most ▁advanced ▁position ▁on ▁the ▁Is á ben a . ▁Both ▁faced ▁the ▁form id able ▁city ▁of ▁Gra us , ▁which ▁was ▁un success fully ▁bes ie ged ▁as ▁early ▁as ▁ 1 0 5 5 ▁and ▁again ▁in ▁ 1 0 6 3 ▁with ▁dis astr ous ▁results , ▁finally ▁falling ▁to ▁the ▁Christians ▁on ▁ 1 4 ▁April ▁ 1 0 8 3 . ▁By ▁ 1 0 8 3 ▁all ▁lands ▁north ▁of ▁the ▁Sierra ▁de ▁Est ada ▁were ▁in ▁Arag on ese ▁hands . ▁On ▁the ▁other ▁side ▁of ▁the ▁Cin ca ▁the ▁town ▁of ▁C aste j ón ▁de ▁Sob rar be ▁fell ▁in ▁ 1 0 5 7 ▁and ▁that ▁of ▁Ab iz anda ▁in ▁ 1 0 5 9 , ▁but ▁further ▁progress ▁was ▁slower . ▁Naval , ▁which ▁was ▁essential ▁to