ABSTRACT
There is no doubt that the expansion of indigo cultivation for commercial purposes throughout the Arab world coincided with the Great Age of Islam. What is harder to identify is the progression of its spread worldwide throughout history, since tracing the diffusion of crops, including indigo, is complicated. Opinions differ both about domestication of the plant and about diffusion of technical knowledge concerning both dye-extraction and dyeing. Some consider that the knowledge to use local indigo plants for dyeing emerged independently in different areas of the world. 1 To others it seems almost miraculous that the complicated technologies of indigo production and dyeing should have been discovered independently by people of differing cultures; they prefer to seek a diffusion of knowledge, often linked with a botanical expansion. In the case of indigo in the Arab world both viewpoints appear to be valid. Here, as in other parts of the world as far apart as China and Central America, the indigenous indigo-producing plants have been exploited to produce a blue dye since prehistory. But this does not preclude the introduction of more efficient indigo species and production techniques for commercial exploitation at a later stage, and this certainly appears to have been the case in the mediaeval Arab world.
