The Romance of Leonardo da Vinci

In Florence the guild of dyers had their shops hard by the Canonica of Orsanmichele. The houses were disfigured by every sort of shed, outhouse, and projection on crooked wooden supports; tiled roofs leaned so close to each other as almost to shut out the sky, and the street was dark even in the glare of noon. In the doorways below, samples of foreign woollen-stuffs were suspended, sent to Florence to be dyed with litmus-lichen, with madder, or with woad steeped in a corrosive of Tuscan alum. The street was paved roughly, and in the kennel flowed many-coloured streams, oozings from the dye vats. Shields over the portals of the principal shops, or Fondachi were blazoned with the arms of the Calimala (so the guild of dyers was named), 'on a field gules, an eagle or, upon a ball of wool argent.'