An organized long-term enterprise of discovery, the Portuguese achievement was more modern, more revolutionary than the more widely celebrated exploits of Columbus. For Columbus pursued a course suggested by ancient and medieval sources, the best information of his day, and if he had succeeded in his avowed purpose, he would have confirm them. There was no uncertainty in his mind either about the landscape en route to Asia or about the direction to be taken. Only the sea was unknown. Columbus’ courage was in taking a direct sea passage to “known” lands in a known direction but without knowing precisely how long the passage might be.

“The Portuguese Discoverers”, from “The Discoverers”, Daniel J. Boorstin, The National Board for the Celebration of Portuguese Discoveries, Lisbon, 1987