What Viking merchants had in mind : Exploring Islamic weight standards and weighing practices within early medieval trading networks

In the Early Middle Ages, with the rise of the Muslim Caliphate trade and exchange expanded on a global scale. Both archaeological and numismatic sources testify to the development of a supra-regional bullion silver economy in Eurasia, which copied monetary standards and practices current in the commerce of the Islamic world. However, we still know little about the monetary habitus in long distance networks of the Early Viking Age (c. 800-950 AD). In this paper, various aspects of measurement, numeracy and units are presented and discussed. It is argued that Viking Age merchants had a profound knowledge of Islamic coinages and their monetary value. They could probably recognise Cufic script and were able to distinguish between dirhams of different emissions by recognising their design, the presence or absence of Cufic letters or signs. Based on observations from an Ethiopian gold merchants weighing gear it is argued that coins and seeds together were used as a means for calibration. Similar practices could also explain the spread and acceptance of weight standards such as the Islamic miṯqāl