Weighing the Baghdādī Raṭl: A Metrological Muddle

Abstract This study addresses a metrological muddle: attempts to determine the metrical equivalence of the Baghdādī raṭl, a measure for coins, commerce, and religious requirements during the Abbasid and Mamluk eras. Western writers Sauvaire and Hinz interpreted the measure of the widespread Baghdādī raṭl by determining a metric equivalent around three grams for the building block of the silver dirham weight. Islamic scholars, however, proposed three different dirham amounts for this raṭl and noted that there were two different ways of determining the standard ratio of the dirham to the dinar. These scholars applied the Baghdādī raṭl of their day to determine the weights of two earlier measures, the ṣāʿ and the mudd from the time of the Prophet Muḥammad. The study of Islamic era metrology has received little critical attention, apart from the field of numismatics, since the work of Walther Hinz, last updated in 1970. I provide a prolegomenon for the need to reread both earlier Muslim authors and the seminal works of Don Vasquez Queipo, Henri Sauvaire and others. Suggestions for approaching the interpretation of Islamic era weights and measures are provided.