▁of ▁the ▁dominant ▁square ▁rig ▁by ▁setting ▁the ▁s ails ▁more ▁fore - and - aft ▁– ▁along ▁the ▁line ▁of ▁the ▁ke el ▁– ▁rather ▁than ▁ath wart ship , ▁while ▁tail oring ▁the ▁l uff ▁and ▁le ech . ▁▁ ▁Both ▁types ▁of ▁late en ▁were ▁likely ▁used ▁from ▁an ▁early ▁date ▁on : ▁a ▁ 2 nd - century ▁AD ▁grav estone ▁dep ict s ▁a ▁quad ril ater al ▁late en ▁sail ▁( also ▁known ▁as ▁a ▁set te e ), ▁while ▁a ▁ 4 th - century ▁m osa ic ▁shows ▁a ▁tri angular ▁one ▁which ▁was ▁to ▁become ▁the ▁standard ▁rig ▁throughout ▁the ▁Middle ▁A ges . ▁According ▁to ▁the ▁Belg ian ▁mar itime ▁historian ▁Luci en ▁Bas ch , ▁the ▁true ▁late en ▁rig ▁appears ▁as ▁early ▁as ▁the ▁ 1 st ▁century ▁BC , ▁in ▁a ▁H ellen istic ▁wall ▁painting ▁found ▁in ▁a ▁Hyp oge um ▁in ▁Alexand ria . ▁The ▁earliest ▁arch ae olog ically ▁exc av ated ▁ship ▁that ▁has ▁been ▁re construct ed ▁with ▁a ▁late en ▁rig ▁is ▁dated ▁to ▁ca . ▁ 4 0 0   AD ▁( Y ass i ▁Ada ▁II ), ▁with ▁a ▁further ▁four ▁being ▁att ested ▁prior ▁to ▁the ▁Arab ▁advance ▁to ▁the ▁Mediter rane an . ▁The ▁Kel ender is ▁ship ▁m osa ic ▁( late ▁ 5 th ▁to ▁early ▁ 6 th ▁century ) ▁and ▁the ▁K ell ia ▁ship ▁gra ff ito ▁from ▁the ▁early ▁ 7 th ▁century ▁complement