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
Trade and use of saffron well-to-do monks wore a long linen undershirt known as a "léine", which was traditionally dyed with saffron. In histology the hematoxylin-phloxine-saffron (HPS) stain and Movat's pentachrome stain are used as a tissue stain to make biological structures more visible under a microscope. Saffron stains collagen yellow. There have been many attempts to replace saffron with a cheaper dye. Saffron's usual substitutes in food—turmeric and safflower, among others—yield a garishly bright yellow that could hardly be confused with that of saffron. Saffron's main colourant is the carotenoid crocin; it has been discovered in the less tediously harvested—and hence less costly—gardenia fruit.