Cotton (Old World)

Old World cotton (Gossypium arboreum and G. herbaceum) was domesticated in the Indus Valley around 5500 BCE, completely independently from New World cotton on the other side of the planet. This parallel domestication—different species, different continents, same outcome—demonstrates that cotton cultivation was not accidental discovery but inevitable emergence wherever fiber-using cultures encountered suitable plants.

The adjacent possible for Indus Valley cotton required the convergence of wild African cotton species (which had spread to South Asia), established linen and wool processing traditions that could transfer to new fibers, and agricultural economies capable of supporting non-food crops. The Indus Valley provided all three: wild cotton growing along riverbanks, textile traditions inherited from earlier cultures, and the surplus agriculture that allowed land to be dedicated to fiber rather than food.

Cotton's advantages over linen drove rapid adoption. While flax requires retting, breaking, and scutching before spinning, cotton bolls need only separation from seeds—a simpler process yielding soft, absorbent fabric that breathed in tropical heat. For the monsoon climate of South Asia, cotton was functionally superior to any alternative fiber.

The Indus Valley cotton industry achieved sophistication unmatched elsewhere for millennia. Mohenjo-Daro and Harappa produced standardized thread gauges, suggesting organized production; cotton fragments from these sites show weaving quality that would not be surpassed until medieval times. When Greek observers later described Indian muslins as 'woven wind,' they were describing an industry already 5,000 years old.

This cotton tradition would eventually transform the world economy. Indian cotton textiles dominated Eurasian trade for two millennia; the desire to replicate Indian fabric quality drove the British Industrial Revolution; and the industrial production of cotton reshaped labor systems across the Americas. The plant domesticated along Indus tributaries 7,500 years ago became the commodity that built and destroyed empires.