Rose madder in the context of Purpurin (dye)

The Unicorn Tapestries or the Hunt of the Unicorn (French: La Chasse à la licorne) is a series of seven tapestries made in the Southern Netherlands around 1495–1505, and now in The Cloisters in New York City. They were possibly designed in Paris and woven in Brussels. They depict a group of noblemen and hunters in pursuit of a unicorn through an idealised French landscape. The tapestries were woven in wool, metallic threads, and silk. The vibrant colours, still evident today, were produced from dye plants: weld (yellow), madder (red), and woad (blue).

First recorded in 1680 in the Paris home of the Rochefoucauld family, the tapestries were looted during the French Revolution. Rediscovered in a barn in the 1850s, they were hung at the family's Château de Verteuil. Since then they have been the subject of intense scholarly debate about the meaning of their iconography, the identity of the artists who designed them, and the sequence in which they were meant to be hung. Although various theories have been put forward, currently nothing is known of their early history or provenance. Their dramatic but conflicting narratives have inspired multiple readings, from chivalric to Christological. Variations in size, style, and composition suggest they come from more than one set, linked by their subject matter, provenance, and the mysterious AE monogram which appears in each. One of the panels, "The Mystic Capture of the Unicorn", survives as just two fragments.

Alizarin (also known as 1,2-dihydroxyanthraquinone, Mordant Red 11, C.I. 58000, and Turkey Red) is an organic compound with formula C₁₄H₈O₄ that has been used throughout history as a red dye, principally for dyeing textile fabrics. Historically it was derived from the roots of plants of the madder genus. In 1869, it became the first natural dye to be produced synthetically.

Alizarin is the main ingredient for the manufacture of the madder lake pigments known to painters as rose madder and alizarin crimson. Alizarin in the most common usage of the term has a deep red color, but the term is also part of the name for several related non-red dyes, such as Alizarine Cyanine Green and Alizarine Brilliant Blue. A use of alizarin in modern times is as a staining agent in biological research because it stains free calcium and certain calcium compounds a red or light purple color. Alizarin continues to be used commercially as a red textile dye, but to a lesser extent than in the past.

George Field (1777?–1854), was an English chemist. He was born in or about 1777 at Berkhamsted, Hertfordshire, of a family long settled in that town, and was educated at St. Peter's school there. When about eighteen years of age he came to London to seek a profession. He thought he saw an opening in the careful application of chemistry to pigments and dyes. War on the continent, by stopping the supply of madder from Holland, threatened to impede his progress. This obstacle, however, led him to consider the nature of its cultivation, and with a well-devised project he waited on Sir Joseph Banks for his advice, and, as he hoped, his co-operation. Sir Joseph, after unsuccessfully attempting to cultivate madder in Essex, had made up his mind that it could not be done in England.