Now it is a fact that neither the letters nor this history makes any statement as to Gerbert's contact with the Saracens. The letters do not speak of the Moors, of the Arab numerals, nor of Cordova. Spain is not referred to by that name, and only one Spanish scholar is mentioned. In one of his letters he speaks of Joseph Ispanus,[456] or Joseph Sapiens, but who this Joseph the Wise of Spain may have been we do not know. Possibly {116} it was he who contributed the morsel of knowledge so imperfectly assimilated by the young French monk.[457] Within a few years after Gerbert's visit two young Spanish monks of lesser fame, and doubtless with not that keen interest in mathematical matters which Gerbert had, regarded the apparently slight knowledge which they had of the Hindu numeral forms as worthy of somewhat permanent record[458] in manuscripts which they were transcribing. The fact that such knowledge had penetrated to their modest cloisters in northern Spain--the one Albelda or Albaida--indicates that it was rather widely diffused. Gerbert's treatise _Libellus de numerorum divisione_[459] is characterized by Chasles as "one of the most obscure documents in the history of science."[460] The most complete information in regard to this and the other mathematical works of Gerbert is given by Bubnov,[461] who considers this work to be genuine.[462] {117} So little did Gerbert appreciate these numerals that in his works known as the _Regula de abaco computi_ and the _Libellus_ he makes no use of them at all, employing only the Roman forms.[463] Nevertheless Bernelinus[464] refers to the nine [.g]ob[=a]r characters.[465] These Gerbert had marked on a thousand _jetons_ or counters,[466] using the latter on an abacus which he had a sign-maker prepare for him.[467] Instead of putting eight counters in say the tens' column, Gerbert would put a single counter marked 8, and so for the other places, leaving the column empty where we would place a zero, but where he, lacking the zero, had no counter to place. These counters he possibly called _caracteres_, a name which adhered also to the figures themselves. It is an interesting speculation to consider whether these _apices_, as they are called in the Boethius interpolations, were in any way suggested by those Roman jetons generally known in numismatics as _tesserae_, and bearing the figures I-XVI, the sixteen referring to the number of _assi_ in a _sestertius_.[468] The {118} name _apices_ adhered to the Hindu-Arabic numerals until the sixteenth century.[469]