I've done glib dismissals, one-liners, and now: crow pie.
Previously dismissed by me in favor of Scandal, Lanvin's (original) Rumeur parfum I now acknowledge to be a wonder. I've become more attuned to the scent of costus nowadays, since I fell for Muscs Koublai Khan, and now the vintage Rumeur is unfolding depths I just didn't catch before. The clove that had seemed so overpowering and medicinal now shifts back and forth from spice to floral quite mesmerizingly, taming the unwashed-hair and wine-soaked-leather character of costus (although I'm sure the effect is created in combination with other chypre-ish basenotes, of course) in the drydown. It's poetically unwashed, as in "I just spent two weeks swaying on the back of this damn camel, staring at the desert, and I'm not quite ready for civilization yet."
Frustratingly, I've found nearly nothing about this perfume's history or descriptions of what it originally smelled like, but Octavian of 1000fragrances has a post about costus in which he identifies it in the older formulations of fragrances including Cabochard and Rumeur. Now it jumps out at me in both. What does costus smell like? Well, apart from the camel-driver's-armpit allusions often pulled out for musky scents like Muscs Koublai Khan, this source describes the scent as "at first like violets, but as it ages it can become more fur-like or eventually become unpleasantly goat-like." Is the goat-like quality what makes it seem so challenging but at the same time makes me think: man, that's some good stink? Mmm, goat. Okay, well, I hope it's the furry quality, not the goat.
Like many plants/resins/etc. mentioned in ancient texts, there is a lot of confusion about whether what the ancient world knew as costus is the same as what we know today. In Pliny's natural history, he says that costus "has a burning taste in the mouth and most exquisite odor," and that a locale renowned for its white costus was the island of Patale, at the mouth of the Indus River, which is in present-day Pakistan. I can't find many geographic records of Patale online, although some studies of ancient Indus Valley civilizations say that Patale was a name for the land of the Indus delta.
Pliny's description is unlikely the costus we talk about today in perfumery, though, given that plant directories like this source on costus (scientific name Saussurea lappa or Saussurea costus) identifies it as a high-altitude plant known to grow at the other end of the Indus, in the Himalayas. I love all the common names for costus that this source lists: kuth, kushta, patchak, and mu xiang, to name a few. It has a long list of medicinal attributes, and it has long been used in both Chinese and Ayurvedic medicines. Maybe Pliny was confusing Saussurea lappa with the tropical herbaceous family of plants named the Costaceae, also known as spiral gingers. Nigel Groom's The New Perfume Handbook also identifies costus as a Himalayan plant. Interestingly, he says it may also have been cultivated in Arabia and used in early perfumes there.
Why I'm idly digressing on the history of costus is that I really enjoy imagining the extension back into ancient history of the elaborate links between geography, botany, trade, medicine, and perfumery, romanticization though it certainly is. The sophisticated (inaccuracies just add to the sense of a wild, unreliable, exquisitely varied world) reports of location, characteristics, cultivation, and value as a commodity reveal the ravenous acquisitory lust of empire that doesn't seem much different from the hunt for the new new thing today. Pliny notes both sources and costs in dinarii when he catalogs botanical finds; he's scouting resources for Rome, isn't he? It's both disturbing and exhilarating. What a find! What precious treasures are still hidden in the Himalayas, or at the Indus River delta, that we may lose or find today? Do we exploit or revere if we seek them? Does it have to be one or the other? Good questions for a perfume-lover, I suppose.
Image is of the Indus River, which I got here.