any to mean a
traveler, and was naturally assumed by one who had studied, as Leonardo
had, in foreign lands.

Leonardo's father was a commercial agent at Bugia, the modern Bougie,[529]
the ancient Saldae on the coast of Barbary,[530] a royal capital under the
Vandals and again, a century before Leonardo, under the Beni Hammad. It had
one of the best harbors on the coast, sheltered as it is by Mt. Lalla
Guraia,[531] and at the close of the twelfth century it was a center of
African commerce. It was here that Leonardo was taken as a child, and here
he went to school to a Moorish master. When he reached the years of young
manhood he started on a tour of the Mediterranean Sea, and visited Egypt,
Syria, Greece, Sicily, and Provence, meeting with scholars as well as with
{131} merchants, and imbibing a knowledge of the various systems of numbers
in use in the centers of trade. All these systems, however, he says he
counted almost as errors compared with that of the Hindus.[532] Returning
to Pisa, he wrote his _Liber Abaci_[533] in 1202, rewriting it in
1228.[534] In this work the numerals are explained and are used in the
usual computations of business. Such a treatise was not destined to be
popular, however, because it was too advanced for the mercantile class, and
too novel for the conservative university circles. Indeed, at this time
mathematics had only slight place in the newly established universities, as
witness the oldest known statute of the Sorbonne at Paris, dated 1215,
where the subject is referred to only in an incidental way.[535] The period
was one of great commercial activity, and on this very {132} account such a
book would attract even less attention than usual.[536]

It would now be thought that the western world would at once adopt the new
numerals which Leonardo had made known, and which were so much superior to
anything that had been in use in Christian Europe. The antagonism of the
universities would avail but little, it would seem, against such an
improvement. It must be remembered, however, that there was great
difficulty in spreading knowledge at this time, some two hundred and fifty
years before printing was invented. "Popes and princes and even great
religious institutions possessed far fewer books than many farmers of the
present age. The library belonging to the Cathedral Church of San Martino
at Lucca in the ninth century contained only nineteen volumes of
abridgments from ecclesiastical comment