rned, paid a secret visit to Mecca and to Medina,
crossed the Red Sea once more and in the year 1490 he discovered the
realm of Prester John, who was no one less than the Black Negus (or
King) of Abyssinia, whose ancestors had adopted Christianity in the
fourth century, seven hundred years before the Christian missionaries
had found their way to Scandinavia.

These many voyages had convinced the Portuguese geographers and
cartographers that while the voyage to the Indies by an eastern
sea-route was possible, it was by no means easy. Then there arose a
great debate. Some people wanted to continue the explorations east of
the Cape of Good Hope. Others said, "No, we must sail west across the
Atlantic and then we shall reach Cathay."

Let us state right here that most intelligent people of that day were
firmly convinced that the earth was not as flat as a pancake but was
round. The Ptolemean system of the universe, invented and duly described
by Claudius Ptolemy, the great Egyptian geographer, who had lived in the
second century of our era, which had served the simple needs of the men
of the Middle Ages, had long been discarded by the scientists of the
Renaissance. They had accepted the doctrine of the Polish mathematician,
Nicolaus Copernicus, whose studies had convinced him that the earth
was one of a number of round planets which turned around the sun, a
discovery which he did not venture to publish for thirty-six years
(it was printed in 1548, the year of his death) from fear of the Holy
Inquisition, a Papal court which had been established in the thirteenth
century when the heresies of the Albigenses and the Waldenses in France
and in Italy (very mild heresies of devoutly pious people who did
not believe in private property and preferred to live in Christ-like
poverty) had for a moment threatened the absolute power of the bishops
of Rome. But the belief in the roundness of the earth was common
among the nautical experts and, as I said, they were now debating the
respective advantages of the eastern and the western routes.

Among the advocates of the western route was a Genoese mariner by the
name of Cristoforo Colombo. He was the son of a wool merchant. He seems
to have been a student at the University of Pavia where he specialised
in mathematics and geometry. Then he took up his father's trade but
soon we find him in Chios in the eastern Mediterranean travelling on
business. Thereafter we hear of voyages to England