commentaries by university lecturers are found.
Probably the most widely used of these was that of Petrus de Dacia[544]
written in 1291. These works throw an interesting light upon the method of
instruction in mathematics in use in the universities from the thirteenth
even to the sixteenth century. Evidently the text was first read and copied
by students.[545] Following this came line by line an exposition of the
text, such as is given in Petrus de Dacia's commentary.

Sacrobosco's work is of interest also because it was probably due to the
extended use of this work that the {135} term _Arabic numerals_ became
common. In two places there is mention of the inventors of this system. In
the introduction it is stated that this science of reckoning was due to a
philosopher named Algus, whence the name _algorismus_,[546] and in the
section on numeration reference is made to the Arabs as the inventors of
this science.[547] While some of the commentators, Petrus de Dacia[548]
among them, knew of the Hindu origin, most of them undoubtedly took the
text as it stood; and so the Arabs were credited with the invention of the
system.

The first definite trace that we have of an algorism in the French language
is found in a manuscript written about 1275.[549] This interesting leaf,
for the part on algorism consists of a single folio, was noticed by the
Abbe Leboeuf as early as 1741,[550] and by Daunou in 1824.[551] It then
seems to have been lost in the multitude of Paris manuscripts; for although
Chasles[552] relates his vain search for it, it was not rediscovered until
1882. In that year M. Ch. Henry found it, and to his care we owe our
knowledge of the interesting manuscript. The work is anonymous and is
devoted almost entirely to geometry, only {136} two pages (one folio)
relating to arithmetic. In these the forms of the numerals are given, and a
very brief statement as to the operations, it being evident that the writer
himself had only the slightest understanding of the subject.

Once the new system was known in France, even thus superficially, it would
be passed across the Channel to England. Higden,[553] writing soon after
the opening of the fourteenth century, speaks of the French influence at
that time and for some generations preceding:[554] "For two hundred years
children in scole, agenst the usage and manir of all other nations beeth
compelled for to leave hire own language, and for to construe hir lessons
and hire thyng