icas . ▁ ▁The ▁Mag ellan - El cano ▁circ umn avigation ▁was ▁the ▁first ▁known ▁voyage ▁around ▁the ▁world ▁in ▁human ▁history . ▁It ▁was ▁a ▁Spanish ▁expedition ▁that ▁sa iled ▁from ▁Se ville ▁in ▁ 1 5 1 9 ▁under ▁the ▁command ▁of ▁Portuguese ▁navig ator ▁Ferdinand ▁Mag ellan ▁in ▁search ▁of ▁a ▁mar itime ▁path ▁from ▁the ▁Amer icas ▁to ▁the ▁East ▁Asia ▁across ▁the ▁Pacific ▁Ocean . ▁Following ▁Mag ellan ' s ▁death ▁in ▁M act an ▁( Ph ili pp ines ) ▁in ▁ 1 5 2 1 , ▁Juan ▁Sebast i án ▁El cano ▁took ▁command ▁of ▁the ▁expedition , ▁sail ing ▁to ▁Bor neo , ▁the ▁Sp ice ▁Islands ▁and ▁back ▁to ▁Spain ▁across ▁the ▁Indian ▁Ocean , ▁round ▁the ▁Cape ▁of ▁Good ▁Hope ▁and ▁north ▁along ▁the ▁west ▁coast ▁of ▁Africa . ▁They ▁arrived ▁in ▁Spain ▁three ▁years ▁after ▁they ▁left , ▁in ▁ 1 5 2 2 . ▁ ▁: ▁Portuguese ▁cart ograph er ▁Pedro ▁Rein el ▁made ▁the ▁oldest ▁known ▁signed ▁Portuguese ▁na ut ical ▁chart . ▁▁ 1 4 9 2 : ▁Cart ograph er ▁Jorge ▁de ▁Ag ui ar ▁made ▁the ▁oldest ▁known ▁signed ▁and ▁dated ▁Portuguese ▁na ut ical ▁chart . ▁▁ 1 5 3 7 : ▁Much ▁of ▁Portuguese ▁math ematic ian ▁and ▁cosm ograph er ▁Pedro ▁N unes ' ▁work ▁related ▁to ▁navigation . ▁He ▁was ▁the ▁first ▁to ▁understand ▁why ▁a ▁ship ▁maintain ing ▁a ▁steady ▁course ▁would ▁not ▁travel ▁along ▁a ▁great ▁circle , ▁the ▁short