It is interesting to note that fish sauce was also used by the Ancient Greeks and Romans. There is evidence that these ancient cultures produced fish sauce on a very large scale and that there was commerce of fish sauce across many regions. In Ancient Greece, the fish sauce was called Garon, and in Ancient Rome, it was called Garum or Liquamen. According to ancient written records it appears that the method of production is very similar to the traditional methods of fish sauce production in Southeast Asia.

The fish sauce produced in ancient times most likely had a high level of glutamate as the production methods were similar to those of the fish sauces in Southeast Asia today.
Therefore, the appreciation of glutamate taste or umami can be traced back to over 2,500 years ago.

Ancient Greece: Garon
Ancient Rome: Garum, Liwuamen

Produced around the Mediterranean Coast and Black sea
Written evidence for fish sauce production 2,500 years ago

Humans have umami receptors. Umami is a basic taste. Humans have developed methods for food processing which enrich foods with free amino acids, in particular glutamate, indicating that the glutamate taste has been desired throughout the history.
Early evidence of such processes can be seen in the fish sauces of Ancient Greece and Rome over 2,500 years ago.

Umami is a taste that has been desired throughout human civilization.
Current umami ingredients such as glutamate and nucleotides are a natural development, allowing us to use the purer forms of umami.