I was reading about the excavations at Berenike. Among the several finds of trade goods which involves pepper, teak and other items from the Indian coast there is also mention of amphoraes that used to contain 'fish sauce'. What is fish sauce? how was it made? what type of fish was used? What uses did this substance have in roman society?
This older answer from u/jdwright1989 does a nice job covering some of the basics of this Roman condiment, as well as some bonus discussion of why it fell out of use!