More Evidence Needed to Map Portugal’s Role

Your story “Portugal May Have Put America on the Map” (Oct. 6) not only has Magellan as the first European to have officially sighted the Pacific (it was Balboa) but also repeats an old idea as if it were completely new: that an unknown Portuguese explorer ventured as far north as present-day Acapulco up the west side of the Americas, that this was kept “secret” for reasons of state by the Portuguese but that somehow the German cartographer Martin Waldseemueller incorporated this “discovery” into his world map of 1507. A book published in 1921 raised the same claims (Edward L. Stevenson’s “Terrestrial and Celestial Globes,” Volume I) but, alas, also provided no evidence for them.

I find more plausible the idea of Eviatar Zerubavel (in “Terra Cognita: The Mental Discovery of America”) that much of European cartography of the “New World” in the 16th century was largely speculative. Waldseemueller, for example, portrayed North America as separate from Asia when this was not known for sure until demonstrated by Captain Cook 271 years later.

Why an armchair explorer like Waldseemueller, sitting in his study in the small town of Saint-Die in the Vosges Mountains, would be privy to the secrets of the king of Portugal needs some explanation. A former CIA analyst like Peter Dickson, the author of the “new” claims, should know how much modern intelligence is based on guesswork rather than on firm evidence (witness disputes over contemporary Iraq’s weapons of mass destruction). The same went for Renaissance-era cartography.

John Agnew

Professor of Geography

UCLA