cope ▁of ▁al li ances ") ▁with ▁multiple ▁powers ▁v ying ▁for ▁domin ance ▁of ▁the ▁Western ▁Mediter rane an , ▁complicated ▁by ▁the ▁un stable ▁relations ▁of ▁Muslim ▁Gran ada ▁with ▁the ▁Mar in id ▁Sultan ate . ▁The ▁conflict ▁reached ▁a ▁clim ax ▁in ▁the ▁ 1 3 4 0 ▁Battle ▁of ▁Río ▁Sal ado , ▁when , ▁this ▁time ▁in ▁al liance ▁with ▁Gran ada , ▁the ▁Mar in id ▁Sultan ▁( and ▁C ali ph ▁pret ender ) ▁Ab u ▁al - Has an ▁Ali ▁ibn ▁O th man ▁made ▁the ▁last ▁Mar in id ▁attempt ▁to ▁set ▁up ▁a ▁power ▁base ▁in ▁the ▁I ber ian ▁Pen ins ula . ▁The ▁last ing ▁consequences ▁of ▁the ▁res ounding ▁Muslim ▁defeat ▁to ▁an ▁al liance ▁of ▁Cast ile ▁and ▁Portugal ▁with ▁naval ▁support ▁from ▁Arag on ▁and ▁Gen oa ▁ens ured ▁Christian ▁supre m acy ▁over ▁the ▁I ber ian ▁Pen ins ula ▁and ▁the ▁pre em in ence ▁of ▁Christian ▁fle ets ▁in ▁the ▁Western ▁Mediter rane an . ▁ ▁The ▁ 1 3 4 8 – 1 3 5 0 ▁b ub onic ▁pl ague ▁dev ast ated ▁large ▁parts ▁of ▁the ▁I ber ian ▁Pen ins ula , ▁leading ▁to ▁a ▁sudden ▁economic ▁ce ase . ▁Many ▁settlement s ▁in ▁northern ▁Cast ile ▁and ▁Catal onia ▁were ▁left ▁for s aken . ▁The ▁pl ague ▁had ▁the ▁start ▁of ▁the ▁host ility ▁and ▁down right ▁violence ▁towards ▁religious ▁minor ities ▁( part icular ly ▁the ▁Jews