▁BC . ▁This ▁is ▁the ▁earliest ▁known ▁set ▁of ▁Greek ▁per ip lo i , ▁or ▁sail ing ▁instructions , ▁which ▁became ▁the ▁basis ▁for ▁many ▁future ▁map m akers , ▁especially ▁in ▁the ▁medieval ▁period . ▁ ▁The ▁way ▁in ▁which ▁the ▁ge ographical ▁knowledge ▁of ▁the ▁Gree ks ▁advanced ▁from ▁the ▁previous ▁assumptions ▁of ▁the ▁Earth ' s ▁shape ▁was ▁through ▁Her odot us ▁and ▁his ▁concept ual ▁view ▁of ▁the ▁world . ▁This ▁map ▁also ▁did ▁not ▁surv ive ▁and ▁many ▁have ▁spec ulated ▁that ▁it ▁was ▁never ▁produced . ▁A ▁possible ▁reconst ruction ▁of ▁his ▁map ▁is ▁displayed ▁below . ▁ ▁Her odot us ▁tra ve led ▁very ▁extens ively , ▁collect ing ▁information ▁and ▁document ing ▁his ▁find ings ▁in ▁his ▁books ▁on ▁Europe , ▁Asia , ▁and ▁Lib ya . ▁He ▁also ▁combined ▁his ▁knowledge ▁with ▁what ▁he ▁learned ▁from ▁the ▁people ▁he ▁met . ▁Her odot us ▁wrote ▁his ▁Histor ies ▁in ▁the ▁mid - 5 th ▁century ▁BC . ▁Although ▁his ▁work ▁was ▁dedicated ▁to ▁the ▁story ▁of ▁long ▁struggle ▁of ▁the ▁Gree ks ▁with ▁the ▁Pers ian ▁Empire , ▁Her odot us ▁also ▁included ▁everything ▁he ▁knew ▁about ▁the ▁ge ography , ▁history , ▁and ▁pe op les ▁of ▁the ▁world . ▁Thus , ▁his ▁work ▁provides ▁a ▁detailed ▁picture ▁of ▁the ▁known ▁world ▁of ▁the ▁ 5 th ▁century ▁BC . ▁ ▁Her odot us ▁rejected ▁the ▁prev ail ing ▁view ▁of ▁most ▁ 5 th - century ▁BC ▁maps ▁that ▁the ▁earth