Fishy Sauce and a Fishy Date

By Claire Eamer

The Garum Shop in the ancient Roman city of Pompeii was a small business that manufactured and sold a fish sauce called garum that Romans adored. The shop went out of business suddenly and permanently in 79 CE when the nearby volcano, Mount Vesuvius, erupted and buried it, the city, and several other communities under metres of volcanic rock and hot ash.

This is the Triclinium or dining room of a wealthy family
in Pompeii. The diners would have reclined on beds while
eating dishes liberally laced with garum. Claire Eamer photo.

In 1960, archaeologists uncovered the Garum Shop for the first time in 1880 years. Buried with it were six large ceramic containers called dolia and several of the large pottery vessels called amphorae used for everything from wine to -- in this case -- fish processing. The dolia contained the remains of garum in several stages of production, and some of the amphorae contained the well-preserved bones of hundreds of tiny fish.

Fishy flavour

Now, historians have known for centuries that the Romans loved garum and ate it in huge quantities. But they didn't know exactly what it was beyond a liquid made from decomposed, fermented fish, fish blood, fish guts, and other fishy bits. Doesn't sound very appealing, does it? But no one knew how appealing it might be because no one had tasted it in the better part of 2000 years.

A street-food booth in Pompeii. The railings are modern, but the rest of the shop
is just as the owner left it almost 2000 years ago. The counters have large ceramic
containers sunk into them to hold the day's offerings, certainly including garum.
Claire Eamer photo.

And we didn't have a decent recipe. Have you ever tried to recreate your mother's perfect chocolate cake icing or your grandmother's perfect butter tarts? (I have.) Even if you have the original recipe and you know exactly how it should taste, it's not easy. So -- no detailed recipe and no idea of what it should taste like made garum a mystery.

In the last few years, however, archaeological science has reached the point where those garum remains are more than a curiosity. Chemists are analyzing them to determine exactly what went into garum and in what quantities. And archaeozoologists are studying the fish bones to figure out what kind of fish were used.

Fishy calendars

The top is gone from this three-legged table, but the marble lion
feet remain. It was a valued antique. An inscription says it once
belonged to Casca Longus, the first to strike Caesar when he was
murdered in the Roman Senate in 44 BCE. Claire Eamer photo. 

That's where the fishy date comes in. For years, the most widely accepted date for the eruption of Mount Vesuvius was August 24, 79 CE. That was based on a letter written by an eye-witness, Pliny the Younger, whose uncle died in the eruption. But Pliny's letter was written 25 years after the event, and the original disappeared long ago. We only know it from translations and copies, and they don't agree on what the Roman date translates to in modern terms.

Back to the fish. Scientists studying fish bones from the Garum Shop determined that they came from a small Mediterranean fish called the common picarel (Spicara smaris) -- and that all the fish examined were 10 to 13 centimetres long, about a year old, and all female. Fish have growth rings in their bones, much like the growth rings of trees, so the scientists could even tell that they died when the water was warmest -- late summer or early autumn. Then they were thrown whole into amphorae and packed with brine and, probably, herbs. They had been in the amphorae from one to three or four weeks when the heavens rained hot ash and buried them.

The August 24 date for the eruption was already in doubt because of other archaeological evidence, and the fish evidence made it even fishier. Large shoals of female-only picarel come close to the shores of southern Italy in late August and September, so that would push the eruption date to mid-October or later.

Fish-free evidence

Huge millstones still sit in the courtyard
of a Pompeii bakery and flour mill.
Claire Eamer photo

Just a year or so ago, an even more definitive piece of evidence for a later date turned up -- a bit of writing scrawled on a wall in charcoal. It's just a date, probably left by a tradesman working on a house, but the date translates to October 17 in our calendar, almost two months after the workman should have died in the eruption. The latest guess is that Vesuvius blew its top about October 24.

So fish and a long-dead tradesman appear to have corrected a fishy historical date. And while we still don't know exactly what garum tasted like, the chemists are busy fishing (sorry -- couldn't resist) for the recipe.

References:
Carannante A. The last garum of Pompeii: Archaeozoological analyses on fish remains from the "garum shop" and related ecological inferences. Int J Osteoarchaeol. 2019;29:377-386.

Pompeii: Vesuvius eruption may have been later than thought. BBC News, 16 October 2018. Located at https://www.bbc.com/news/world-europe-45874858.