Colourful rivers: archaeobotanical remains of dye plants from urban fluvial deposits in the southern Low Countries (Belgium)

Although dye plants were a key element in the medieval cloth industry, their use has rarely been documented through archaeobotanical studies. This paper describes and discusses new archaeobotanical finds related to textile dyeing in the southern Low Countries, which was among the most important areas of cloth production and export in Europe during the late medieval period. Remains of weld, madder and woad, the three main medieval dye plant species, were identified via archaeobotanical analysis and high-performance liquid chromatography with photodiode array detection (HPLC-PDA). The remains were found in river deposits, dating between the 10th/12th and 15th century, from two medieval cloth-producing towns, Brussels and Mechelen. Most likely, the finds must be interpreted as waste discarded by textile dyers, which were often concentrated along the urban riverbanks. This study not only documents the use of dye plants in both cities, but also demonstrates the importance of archaeobotanical analyses of fluvial deposits for the reconstruction of artisanal activities within ancient towns. The assemblages are confronted with historic sources and mapped with other medieval remains of dye plants in the region.