ABSTRACT

Prince Henry "the Navigator" sponsored Portuguese navigational efforts, Gil Eanes rounded Cape Bojador in 1434, and Diogo Cao navigated the Congo River in 1471. No group of sailors had traversed the mid-Atlantic and returned despite more than 3,000 years of sailing around the Mediterranean and despite the remarkable success of the Vikings along the Atlantic's northernmost edge. Gil Eanes's rounding Cape Bojador on the northwestern coast of Africa in 1434 constituted a major step forward. It would have been significant even if Portuguese sailors had failed to follow up this voyage with even more spectacular breakthroughs. And as Portuguese sailors headed southward, gradually conquering the previously undefeated Atlantic, they would have to pay great attention to currents as well as winds, succeeding where none had succeeded before in navigating the mid-Atlantic and later the South Atlantic. Eanes's use of triangles to solve the mystery of sailing past Bojador would have been the first application of mathematical principles to sailing.