Prince Henry’s death caused only a brief hiatus in the exploring enterprise. Then in 1469 King Alfonso V, Prince Henry’s nephew, in financial difficulty, found a way to make discovery into a profitable business. In an agreement quite unlike any we have heard of before between sovereign and vassal, Fernão Gomes, a wealthy citizen of Lisbon, committed himself to discover at least one hundred farther leagues, about three hundred miles, of the African coast each year for the next five years. In return, Gomes obtained a monopoly of the Guinea trade, from which the King received a share. The rest of the story has the inevitability of a steadily rising curtain. Discovery of the whole west African coast by the Portuguese now was a question no longer of whether but of when.

The supposed Portuguese policy of secrecy poses tantalizing problems for the historian because the policy itself seems to have been kept secret. When we chronicle Portuguese advances into the hitherto unknown, we must wonder whether any particular Portuguese voyage was unrecorded because of this “policy of secrecy” or simply because it was never made. Portuguese historians have been understandably tempted to treat the absence of a record of pre-Columbian voyages to America as a kind of evidence that such voyages really were made. […]

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