Arithmetic Conventions for Conversion Between Roman [i.e. Ottoman] and Egyptian Measurement


This treatise, written on ten folio pages for an Ottoman official and patron of books known as Ismā‘īl Afandī, is on the inter-conversion of units of measurement. It is a useful guide for merchants and others engaged in the measurement of quantities. It provides instructions for converting arṭāl (plural of raṭl) into uqaq (plural of auqiya), and back; darāhim (plural of dirham) into mathāqīl (plural of mithqāl) and back; and converting the number of Ottoman (referred to as Roman, rūmī) loading bags into the number of Egyptian loading bags (akyās), and vise-versa. It states, for example, “should you want to convert arṭāl into uqaq, multiply [the number of] arṭāl by thirty-six, and then scratch off the two most significant digits…. For instance, if it is asked how many uqaq do twenty-five raṭl convert into? Multiply that number by thirty-six and truncate the two most significant digits, and the answer is nine.” The conversion between Ottoman and Egyptian loading bags is achieved by “dividing the number of Ottoman pouches by five and then multiplying the result by four.” Rules of conversion are summarized in verse form, so they can be memorized and recalled easily. The manuscript was copied in 1642 (1051 A.H.), by a scribe called Muḥammad Shams al-Dīn ibn Muḥammad Faḍl-Allāh al-Anṣārī al-Shāfi‘ī.

Date Created

Subject Date


Title in Original Language

قواعد الحسابية فى تحويلات الأكياس الرومية الى الأكياس المصرية

Type of Item

Physical Description

5 leaves; 19.5 x 14 centimeters


  • Contains small, illustrated tables.

Last updated: September 22, 2014