▁the ▁picture . ▁ ▁By ▁the ▁ 6 th ▁century , ▁the ▁late en ▁sail ▁had ▁largely ▁replaced ▁the ▁square ▁sail ▁throughout ▁the ▁Mediter rane an , ▁the ▁latter ▁almost ▁disappear ing ▁from ▁Mediter rane an ▁icon ography ▁until ▁the ▁mid - 1 3 th ▁century . ▁It ▁became ▁the ▁standard ▁rig ▁of ▁the ▁By z antine ▁d rom on ▁war ▁gal ley ▁and ▁was ▁probably ▁also ▁employed ▁by ▁Bel is arius ' ▁flags hip ▁in ▁the ▁ 5 3 2   AD ▁invasion ▁of ▁the ▁V andal ▁kingdom . ▁The ▁fully ▁tri angular ▁late en ▁and ▁the ▁set te e ▁continued ▁to ▁co exist ▁in ▁the ▁middle ▁By z antine ▁period , ▁as ▁ev iden ced ▁by ▁Christian ▁icon ography , ▁as ▁well ▁as ▁a ▁recent ▁find ▁of ▁a ▁gra ff ito ▁in ▁the ▁Y en ik ap ı ▁exc av ations . ▁In ▁the ▁ 1 2 th ▁to ▁ 1 3 th ▁centuries ▁the ▁rig ging ▁under w ent ▁a ▁change ▁when ▁the ▁hook - sh aped ▁m ast head ▁made ▁way ▁for ▁an ▁arrangement ▁more ▁a kin ▁to ▁a ▁bar rel - like ▁crow ' s ▁nest . ▁ ▁After ▁the ▁Muslim ▁con quest s , ▁the ▁Arab s ▁adopted ▁the ▁late en ▁sail ▁by ▁way ▁of ▁the ▁Co ptic ▁popul ace , ▁which ▁shared ▁the ▁existing ▁Mediter rane an ▁mar itime ▁tradition ▁and ▁continued ▁to ▁provide ▁the ▁bulk ▁of ▁gal ley ▁cre ws ▁for ▁Muslim - led ▁fle ets ▁for ▁centuries ▁to ▁come . ▁This ▁is ▁also ▁indicated