Garum

Garum is a fermented fish sauce that was used as a condiment in the cuisines of Phoenicia, ancient Greece, Rome, Carthage and later Byzantium. Liquamen is a similar preparation, and at times they were synonymous. Although garum enjoyed its greatest popularity in the Western Mediterranean and the Roman world, it was earlier used by the Greeks. Like modern fermented fish sauce and soy sauce, garum was a rich source of umami flavoring due to the presence of glutamates. It was used along with murri in medieval Byzantine and Arab cuisine to give a savory flavor to dishes. Murri may derive from garum. Pliny the Elder and Isidore of Seville derive the Latin word garum from the Greek γάρος , a food named by Aristophanes, Sophocles, and Aeschylus. Garos may have been a type of fish, or a fish sauce similar to garum. Pliny stated that garum was made from fish intestines, with salt, creating a liquor, the garum, and the fish paste named (h)allec or allex (similar to bagoong, this paste was a byproduct of fish sauce production). A concentrated garum evaporated down to a thick paste with salt crystals was called muria; it would have been used to salt and flavor foods.

Source: Wikipedia