Original ketchup had no tomatoes. It was fermented fish sauce.

Somewhere in 17th-century southeastern China, a pungent, fermented fish brine called kê-tsiap was doing what fish sauces do best: making everything taste more alive. It was dark, thin, and had nothing remotely to do with tomatoes.

British and Dutch sailors picked it up during trade voyages and carried it home, where it mutated fast. By the early 1700s, English cooks were making their own versions — swapping the fish for mushrooms, walnuts, even oysters. The word warped too: ke-tsiap, catchup, catsup, ketchup.

The tomato arrived late to the party. American cooks began experimenting with tomato-based ketchup in the early 19th century, and by 1876 Henry J. Heinz had bottled and standardized it into the version that now sits on roughly half the tables in the world.

The fermented fish original never disappeared, though. It just kept its own name. What we call fish sauce today — the backbone of Thai and Vietnamese cooking — is the direct descendant of that same kê-tsiap the sailors once smuggled home in barrels.