Those hardy sailors were the best possible professors for a boy who
intended to follow the sea. They were, doubtless, practical men who
never talked much about the sea-monsters and other nonsense that many
landsmen believed in; nor did they talk of the world being flat, with a
jumping-off place where the sun set. That belief was probably cherished
by men of book-learning only, who lived in convents and who never risked
their lives on the waves. Good men these monks were, and we are grateful
to them for keeping alive a little spark of learning during those long,
rude Middle Ages; but their ideas about the universe were not to be
compared in accuracy with the ideas of the practical mariners to whom
young Cristoforo talked on the gay, lively wharves of _Genova la
Superba_.

Many years after Columbus's death, his son Fernando wrote that his
father had studied geography (which was then called _cosmogony_) at
the University of Pavia. Columbus himself never referred to Pavia nor to
any other school; nor was it likely that poor parents could afford to
send the eldest of five children to spend a year at a far-off
university. Certain it is that he never went there after his seafaring
life began, for from then on his doings are quite clearly known; so we
must admit that while he may have had some teaching in childhood, what
little knowledge he possessed of geography and science were self-taught
in later years. The belief in a sphere-world was already very ancient,
but people who accepted it were generally pronounced either mad or
wicked. Long before, in the Greek and Roman days, certain teachers had
believed it without being called mad or wicked. As far back as the
fourth century B.C. a philosopher named Pythagoras had written that the
world was round. Later Plato, and next Aristotle, two very learned
Greeks, did the same; and still later, the Romans taught it. But Greece
and Rome fell; and during the Dark Ages, when the Greek and Roman ideas