Saffron slowly propagated throughout much of Eurasia and was later brought to parts of North Africa, North America, and Oceania. Saffron was detailed in a 7th-century BC Assyrian botanical reference compiled under Ashurbanipal. Documentation of saffron's use over the span of 3,500 years has been uncovered. Saffron-based pigments have indeed been found in 50,000-year-old depictions of prehistoric places in northwest Iran. The Sumerians later used wild-growing saffron in their remedies and magical potions. Saffron was an article of long-distance trade before the Minoan palace culture's 2nd millennium BC peak. Ancient Persians cultivated Persian saffron ("Crocus sativus" 'Hausknechtii') in Derbent, Isfahan, and
Saffron per gram, given the wide possible range of colouring strengths that different kinds of saffron can have. Despite attempts at quality control and standardisation, an extensive history of saffron adulteration, particularly among the cheapest grades, continues into modern times. Adulteration was first documented in Europe's Middle Ages, when those found selling adulterated saffron were executed under the "Safranschou" code. Typical methods include mixing in extraneous substances like beetroot, pomegranate fibres, red-dyed silk fibres, or the saffron crocus's tasteless and odourless yellow stamens. Other methods included dousing saffron fibres with viscid substances like honey or vegetable oil to increase their weight.