The Hindu-Arabic Numerals c11.138

c11.138

Among the writers on the subject may be mentioned Abbo⁶ of Fleury (c. 970), Heriger⁷ of Lobbes or Laubach (c. 950–1007), and Hermannus Contractus¹ (1013–1054), all of whom employed only the Roman numerals. Similarly Adelhard of Bath (c. 1130), in his work *Regulae Abaci*,² gives no reference to the new numerals, although it is certain that he knew them. Other writers on the abacus who used some form of Hindu numerals were Gerland³ (first half of twelfth century) and Turchill⁴ (c. 1200). For the forms used at this period the reader is referred to the plate on page 88.