The simplest societies have long held indigo in their dyepots, coloring plain cloth from native plants. Yet indigo was also traded along the Silk Road, and dispersed through the European west, eventually becoming a global commodity. Indigo’s wide and deep reach provides a complex history and intersects with many disciplines—religion, early trade, plantation economies, the semiotics of textiles, and the science of color. Over time indigo marked our world both visually and linguistically. NFS