▁is ▁at ▁the ▁top ▁and ▁east ▁to ▁the ▁right ▁of ▁the ▁map — an ▁almost ▁universal ▁custom ▁today . ▁ ▁Yet ▁with ▁all ▁his ▁important ▁innov ations , ▁however , ▁P to le my ▁was ▁not ▁inf al li ble . ▁His ▁most ▁important ▁error ▁was ▁a ▁mis calcul ation ▁of ▁the ▁circum ference ▁of ▁the ▁earth . ▁He ▁believed ▁that ▁E uras ia ▁covered ▁ 1 8 0 ° ▁of ▁the ▁glo be , ▁which ▁convinced ▁Christopher ▁Columb us ▁to ▁sail ▁across ▁the ▁Atlantic ▁to ▁look ▁for ▁a ▁simpler ▁and ▁faster ▁way ▁to ▁travel ▁to ▁India . ▁Had ▁Columb us ▁known ▁that ▁the ▁true ▁figure ▁was ▁much ▁greater , ▁it ▁is ▁conce iv able ▁that ▁he ▁would ▁never ▁have ▁set ▁out ▁on ▁his ▁moment ous ▁voyage . ▁ ▁Tab ula ▁Pe ut inger iana ▁ ▁In ▁ 2 0 0 7 , ▁the ▁Tab ula ▁Pe ut inger iana , ▁a ▁ 1 2 th - century ▁rep lica ▁of ▁a ▁ 5 th - century ▁road ▁map , ▁was ▁placed ▁on ▁the ▁UN ES CO ▁Memory ▁of ▁the ▁World ▁Register ▁and ▁displayed ▁to ▁the ▁public ▁for ▁the ▁first ▁time . ▁ ▁Although ▁well ▁preserved ▁and ▁believed ▁to ▁be ▁an ▁accurate ▁copy ▁of ▁an ▁authentic ▁original , ▁the ▁scroll ▁media ▁it ▁is ▁on ▁is ▁so ▁del icate ▁now ▁it ▁must ▁be ▁protected ▁at ▁all ▁times ▁from ▁expos ure ▁to ▁day light . ▁ ▁China ▁ ▁The ▁earliest ▁known ▁maps ▁to ▁have ▁surv ived ▁in ▁China ▁date ▁to ▁the ▁ 4 th ▁century