The Hindu-Arabic Numerals c12.34

c12.34

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.