[25] On the purchase of blecken by the Duke of Brabant, see Van der Wee, Growth of the Antwerp Market, I: 25, note 123; on preparation of the dye, see Cardon, Natural Dyes, 423 and 425–427; de Nie, De ontwikkeling, 196–9; Hofenk de Graaff, The Colourful Past, 294–295; on the Ypres legislation, see Espinas and Pirenne, Recueil de documents, no. 42, 623–624.