Back to Middle Ages ! Views of the traditional work of the tanners, whose practices have remained unchanged since the 14th century, at the Chouara tannery. It is the largest of the four ancient tanneries still in existence in the medina of Fez and is composed of numerous dried-earth pits where raw skins are treated, pounded, scraped and dyed. Tanners work in vats filled with various coloured liquid dyes derived from plant sources. Colours change every two weeks, poppy flower for red, mint for green, indigo for blue, chedar tree for brown and saffron for yellow.