Ancient Egyptian weavers decorated linen and wool with indigo-blue dye as early as 2000 B.C.E. But the actual source of indigo color in Egypt remains uncertain.
The plant that produces true indigo dye, Indigofera tinctoria, is not known to have grown in Egypt, but was imported through trade routes by the Greco-Roman period (323 B.C.E.–395 C.E.).
The woad plant, which produced a slightly less concentrated indigo color, was likely the earliest source of blue dye in Egypt.