By 1487 King John II had organized a two-pronged grand strategy for reaching the long-sought Christian ally. He would send one expedition southeastward overland and another by sea around the African coast. If there really should be a sea passage to India, a Christian ally was more desirable and more necessary than ever, not only for crusading but also to serve as way station and supply base for future trading enterprises.

The overland expedition that left Santarém on May 7, 1487, like others before it, was characteristically small, consisting of only two men. After a considerable search, the King had chosen Pero da Covilhã (1460?-1545?) and Afonso de Paiva for the dangerous assignment. Covilhã, a married man with children, in his late twenties, had already proven himself bold and versatile. He has spent much of his life abroad, had taken part in ambushes in the streets of Seville, had served as the King’s secret agent at the court of Ferdinand and Isabella, and had undertaken diplomatic missions to the Barbary States in north Africa. […]

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