Toscanelli, Paolo

(1397-1482)

   Florentine astronomer, mathe-matician, and cartographer, best known in his own time as an out-standing mathematician but most famed in modern times because his geographical ideas and his map depicting non-European parts of the world may have encouraged Christopher Columbus in the formula-tion of his plan to reach eastern Asia by sailing west. Toscanelli stud-ied mathematics at the University of Florence and medicine at Padua. At Padua he became a friend of the German scholar Nicholas of Cusa. Toscanelli practiced medicine in Florence from 1424, and since astrological knowledge was an important part of 15th-century medicine, he was expert in that field and in the closely related field of astronomy. He observed and mapped comets and was one of the first to conclude that comets are celestial rather than meteorological (that is, superlunary rather than sublunary) objects. His family's in-volvement in the spice trade may have attracted Toscanelli to specu-late about routes to the oriental source of spices. His miscalculation of the circumference of the earth, based on rejection of the accurate figures of the ancient astronomer Eratosthenes and his acceptance of other Hellenistic astronomers (including the standard authority, Ptolemy) who greatly underestimated the circumference, may have encouraged Columbus to seek his new route to Japan and China. If the letters are not later forgeries (a hotly debated issue among Colum-bus scholars), Columbus corresponded with Toscanelli, receiving a letter and a map that encouraged the plan that he carried out (unsuc-cessfully, as far as reaching East Asia was concerned) in 1492.