Various Subr culture ceramic vessels contained either large bases with the bottom pierced as strainers (9) or open "canisters". An earlier suggestion for the function of these vessels involved indigo processing. The indigo plant, indigenous to the region, produced a deep blue color and the product was used locally in a number of ways by the Bronze Age populations. It was highly desired by the Ancient Egyptians from at least the First Dynasty (ca. 3000 B.C.)