“Few adventures in pursuit of myth were more seductive than the quest for the mythical kingdom of Prester John.”

— Daniel J. Borstin, “The Discoverers”

“How often in his long conversations with travelers and seafarers Prince Henry must have heard that name, Prester John. The search for this long-dead, or non-existent, monarch played as important a part in the history of navigation and discovery as the quest for the philosopher’s stone in the history of chemistry.”

— Earle Bradford, “A Wind from the North; the Life of Henry the Navigator”