Medieval period onwards Isatis tinctoria

illustration of german woad mill in thuringia, 1752

woad 1 of 3 staples of european dyeing industry, along weld (yellow) , madder (red). chaucer mentions use dyer ( litestere ) in poem former age:

no mader, welde, or wood no litestere.
ne knew; flees of former hewe

the 3 colors can seen in tapestries such hunt of unicorn (1495–1505), though typically dark blue of woad has lasted best.

in viking age levels @ archaeological digs @ york, dye shop remains of both woad , madder has been excavated , dated 10th century. in medieval times, centres of woad cultivation lay in lincolnshire , somerset in england, jülich , erfurt area in thuringia in germany, piedmont , tuscany in italy, , gascogne, normandy, somme basin (from amiens saint-quentin), brittany and, above all, languedoc in france. last region, in triangle created toulouse, albi, , carcassonne, long time productive of woad, or pastel known there, 1 writer commenting woad... hath made country happiest , richest in europe. prosperous woad merchants of toulouse displayed affluence in splendid mansions, many of still stand, hôtel de bernuy , hôtel d assézat. 1 merchant, jean de bernuy, spanish jew had fled inquisition, credit-worthy enough main guarantor of ransomed king francis after capture @ battle of pavia charles v of spain. of woad produced here used cloth industry in southern france, exported via bayonne, narbonne , bordeaux flanders, low countries, italy, , above britain , spain.

a major market woad @ görlitz in silesia. citizens of 5 thuringian färberwaid (dye woad) towns of erfurt, gotha, tennstedt, arnstadt , langensalza had own charters. in erfurt, woad-traders gave funds found university of erfurt. traditional fabric still printed woad in thuringia, saxony , lusatia today: known blaudruck (literally, blue print(ing) ).

medieval uses of dye not limited textiles. example, illustrator of lindisfarne gospels used woad-based pigment blue paint.