Magellan’s conception of the world he planned to explore was fatally inaccurate. Like most explorers of the Age of Discovery, his ideas about the size of the globe, and location of landmasses, were inspired by Ptolemy. Had Magellan comprehended the size of the Pacific, its currents, storms, and reefs, it is unlikely that he would have dared to mount an expedition. But without the Pacific Ocean to inform his calculations, the estimated length of his route came to only half the actual distance.
