, ▁but ▁they ▁certainly ▁did ▁prove ▁his ▁idea . ▁He ▁spec ulated ▁that ▁the ▁N ile ▁River ▁started ▁as ▁far ▁west ▁as ▁the ▁I ster ▁River ▁( Dan ube ) ▁in ▁Europe ▁and ▁cut ▁Africa ▁through ▁the ▁middle . ▁He ▁was ▁the ▁first ▁writer ▁to ▁assume ▁that ▁the ▁C asp ian ▁Sea ▁was ▁separated ▁from ▁other ▁se as ▁and ▁he ▁recogn ised ▁northern ▁S cy th ia ▁as ▁one ▁of ▁the ▁col dest ▁inhab ited ▁lands ▁in ▁the ▁world . ▁ ▁Similar ▁to ▁his ▁prede cess ors , ▁Her odot us ▁also ▁made ▁mistakes . ▁He ▁accepted ▁a ▁clear ▁distinction ▁between ▁the ▁civil ized ▁Gree ks ▁in ▁the ▁centre ▁of ▁the ▁earth ▁and ▁the ▁bar b ari ans ▁on ▁the ▁world ' s ▁edges . ▁In ▁his ▁Histor ies ▁we ▁can ▁see ▁very ▁clearly ▁that ▁he ▁believed ▁that ▁the ▁world ▁became ▁stranger ▁and ▁stranger ▁when ▁one ▁tra ve led ▁away ▁from ▁Greece , ▁until ▁one ▁reached ▁the ▁ends ▁of ▁the ▁earth , ▁where ▁humans ▁behav ed ▁as ▁sav ages . ▁ ▁While ▁various ▁previous ▁Greek ▁philosoph ers ▁pres umed ▁the ▁earth ▁to ▁be ▁spher ical , ▁Arist ot le ▁( 3 8 4 – 3 2 2 ▁BC ) ▁is ▁cred ited ▁with ▁prov ing ▁the ▁Earth ' s ▁spher icity . ▁His ▁arguments ▁may ▁be ▁summar ized ▁as ▁follows : ▁ ▁The ▁lun ar ▁eclipse ▁is ▁always ▁circular ▁ ▁Sh ips ▁seem ▁to ▁sink ▁as ▁they ▁move ▁away ▁from ▁view ▁and ▁pass ▁the ▁horizon ▁ ▁Some ▁stars ▁can ▁be ▁seen ▁only ▁from