Cetobriga
About
Twenty-five separate workshops packed the Troia peninsula with 182 salting tanks between them, an industrial concentration UNESCO calls unmatched anywhere else in the Roman world. Tuna and sardines came out of the Sado estuary and went into amphorae as garum bound for the length of the empire. Production here ran continuously from the 1st century into the 6th.
What happened here
Rows of stone vats sunk into the ground beside the sea, and the smell reaches a long way inland. Small fish and the guts of larger ones are layered with salt and left in the sun for weeks; the liquid that separates off is drawn away as fish sauce and the residue is sold cheaply as paste. Grades run from a luxury sauce that costs more than good wine down to the version bought by everyone else. Tunny is netted in season from lookout towers on the headland, and the fishing, salting, potting and shipping all happen within a few hundred metres. Amphorae are stamped with the maker's name. Towns built on this are rich, and they are built downwind of themselves.
Sources
Roman Maps shows the empire frozen at 11 August 117 CE, the day Trajan died — its moment of greatest territorial extent. Explore the full map →