Rui Faleiro

Rui (Ruy) Faleiro [ˈʁuj fɐˈlɐjɾu] was a Portuguese cosmographer, astrologer, and astronomer who was the principal scientific organizer behind Magellan's circumnavigation of the world.

Born in Covilhã, Kingdom of Portugal, at the end of the fifteenth century, Faleiro and his brother Francisco Faleiro, also a cosmographer, served the Spanish king Charles I in Seville. Faleiro, one of the first to apply the most rigorously scientific method of determining latitude and longitude, had earlier served John II of Portugal and his successor, Manuel I of Portugal.

Faleiro was certain that south of the "Terras de Vera Cruz" (i.e. Brazil), at 40 degrees latitude, there was an Atlantic passage that led to the South Seas. The sought-after Spice Islands would, by Faleiro's calculations, fall on the Spanish side of the line of Tordesillas.

The merchant Christopher de Haro helped Faleiro and Magellan present their proposal before the Spanish royal counselors.

Faleiro planned to accompany Magellan on his voyage around the world. However, it is said that on the evening prior to embarkation, Faleiro worked out his own horoscope for the voyage. The stars predicted a violent death. Consequently, he remained behind. Other sources claim he went mad before the voyage, and thus did not join the expedition.