aries."[537] Indeed, it was not
until the early part of the fifteenth century that Palla degli Strozzi took
steps to carry out the project that had been in the mind of Petrarch, the
founding of a public library. It was largely by word of mouth, therefore,
that this early knowledge had to be transmitted. Fortunately the presence
of foreign students in Italy at this time made this transmission feasible.
(If human nature was the same then as now, it is not impossible that the
very opposition of the faculties to the works of Leonardo led the students
to investigate {133} them the more zealously.) At Vicenza in 1209, for
example, there were Bohemians, Poles, Frenchmen, Burgundians, Germans, and
Spaniards, not to speak of representatives of divers towns of Italy; and
what was true there was also true of other intellectual centers. The
knowledge could not fail to spread, therefore, and as a matter of fact we
find numerous bits of evidence that this was the case. Although the bankers
of Florence were forbidden to use these numerals in 1299, and the statutes
of the university of Padua required stationers to keep the price lists of
books "non per cifras, sed per literas claros,"[538] the numerals really
made much headway from about 1275 on.

It was, however, rather exceptional for the common people of Germany to use
the Arabic numerals before the sixteenth century, a good witness to this
fact being the popular almanacs. Calendars of 1457-1496[539] have generally
the Roman numerals, while Koebel's calendar of 1518 gives the Arabic forms
as subordinate to the Roman. In the register of the Kreuzschule at Dresden
the Roman forms were used even until 1539.

While not minimizing the importance of the scientific work of Leonardo of
Pisa, we may note that the more popular treatises by Alexander de Villa Dei
(c. 1240 A.D.) and John of Halifax (Sacrobosco, c. 1250 A.D.) were much
more widely used, and doubtless contributed more to the spread of the
numerals among the common people.

{134}

The _Carmen de Algorismo_[540] of Alexander de Villa Dei was written in
verse, as indeed were many other textbooks of that time. That it was widely
used is evidenced by the large number of manuscripts[541] extant in
European libraries. Sacrobosco's _Algorismus_,[542] in which some lines
from the Carmen are quoted, enjoyed a wide popularity as a textbook for
university instruction.[543] The work was evidently written with this end
in view, as numerous