Two Old Persian Translations of Javāmiʿ al-ḥisāb bi al-takht wa al-turāb : Lubāb al-ḥisāb fi ʿilm al-turāb and Jāmiʿ al-ḥisāb Niẓāmī

Two distinct old Persian translations of Javāmiʿ al-ḥisāb bi al-takht wa al-turāb found thus far are entitled Lubāb al-ḥisāb fi al-turāb and Jāmiʿ al-ḥisāb Niẓāmī, which have been remained unknown in all catalouges; the first due to the similarity of the name with other treatises on arithmetic, and the second, since it has an abridged and selective structure, even though its name is too similar to the original Arabic to not have been confused with other works in the catalogues. The translators of both treatises remain still anonymous but the date of their compilations shouldn’t be after the 8th century AH/about 14th century CE assumed from the literature and codicological features. The structure of Lubāb al-ḥisāb is slightly different from the structure of the original text, and some parts have been omitted in the Persian translation. In addition, the translator has provided the text in a different way in some sections. One of the most notable specifications of Lubāb al-ḥisāb is mentioning Naṣīr al-Dīn al-Ṭūsī by his sobriquets in the text, which confirms the authenticity of the attribution of Javāmiʿ al-ḥisāb to him. Jāmiʿ al-ḥisāb Niẓāmī is also a compendium of Javāmiʿ al-ḥisāb without addressing Ṭūsī’s work as its reference. It comprises only the translation of the first chapter and the first three sections of the second chapter of Javāmiʿ. One of the significant characteristics of Jāmiʿ al-ḥisāb Niẓāmī is describing a special grid tabular multiplication named "Lattice Multiplication" (Żarb-i Šabaka) attributing to Niẓām al-Dīn Nišābūrī, which is thoroughly examined based on textual evidence in the present research.