The Day the Universe Changed - James Burke [39]
The Florentine interest in cartography had been stimulated at the beginning of the century when the group of businessmen to whom Chrysoloras had originally taught Greek, who had been on a tour to Constantinople in search of culture and classical texts, had returned in 1400, after shipwreck and adventure, with a copy of the greatest cartographical text of antiquity, Ptolemy’s Geographica.
Coming as it did at the high point in the early development of humanism, the book created a furore. Many de luxe editions were copied. Besides containing everything known to the Greeks about the earth, the maps in the book were also extraordinary because they were gridded.
The Italians had seen maps before. For over a hundred years they themselves had been using portolan charts - individually produced charts of sections of coastlines, drawn in great detail and carrying the lines of the prevalent winds. But the Geographica mapped the entire known world. Moreover, the material was presented in a consistent and standardised way, with grid lines of latitude and longitude. This metrication of the earth’s surface meant that all points on the map were therefore proportionately distant from each other, and that even unknown locations could be given co-ordinates.
The world map of Ptolemy of Alexandria. In his use of the words terra incognita, unknown lands (bottom left, below ‘ETHIOPIA INTERIOR’), Ptolemy freed explorers from the Aristotelian belief that the South was an uninhabitable region of fire.
Toscanelli was a doctor and, typically for the period, had also studied mathematics. Besides this he was a cartographer and so well placed to investigate whatever cartographic information might be gained from the delegates visiting the Council. At the request of the Portuguese, Toscanelli began to interview any delegate who could tell him anything about the Far East. While the Council was still meeting, a Florentine trader called Andrea da Sarteano returned from the Persian Gulf with a fellow Italian, Niccolo da Conti, whom he had found stranded in Cairo. Conti had spent years in the Far East.
In the same year, 1441, Portuguese interest in exploration was heightened by the discovery of the African Gold Coast, rich in precious metal and equally valuable slaves. The desire to develop long-distance navigational skills became a matter of some urgency.
When Toscanelli had been studying in Padua years before, one of his classmates had been Nicholas, a German from Kues, near Trier, on the banks of the Moselle. Nicholas too was a mathematician, though his initial studies had been in law. Together with Toscanelli he had been inspired by the mathematical teachings of Prodocimo de’ Beldomandi. In 1437, at the behest of the Pope, Nicholas had gone to conduct the Emperor John to the Council at Florence.
Nicholas had a profound admiration for Toscanelli, whom he considered the best mathematician in Europe, and to whom he dedicated several books. He and Toscanelli remained in close contact through the years of Nicholas’s steady rise to the position of Cardinal. In the 1440s Nicholas wrote his great Reconciliation of Opposites, in which he propounded what was the first relativistic view of the universe.
If the universe is infinite then the Earth is not necessarily, or even possibly at its centre. And if that is so, the Earth may well be circling the Sun. It is only the viewpoint of the observer as he stands on the Earth that makes him think it the centre of the universe. The same would be true of anybody standing on the Moon or on any one of the stars and planets there might be in the universe. And if everything were relative to everything else, the only way to know where you were, on Earth or on a planet, would be to find a way to measure the ‘elsewhere’.
This was precisely what the perspective geometry of Brunelleschi would permit: measurement at a distance. It occurred to Toscanelli that, together with