Garum

garum a condiment whose use was fundamental to cookery in classical times. It was made by fermenting fish, as the SE Asian fish sauces, which closely resemble it, are still made.

From the numerous allusions to garum by classical authors, and in particular the descriptions of it given by Pliny (1st century ad) and in the Geoponica (10th century), it is clear that there were many methods of manufacture. Sometimes the entrails of large fish were used; sometimes small fish, whole. Such small fish were often of the genus Atherina (see sand-smelt under silverside), which abounds in the Mediterranean and Black seas, or anchovy or small grey mullet or sea bream, or the like. The larger fish ranged down from the tuna to mackerel.