The lamprey isn’t exactly the world’s most appealing creature: Long, lithe and vaguely eel-like, the fish’s defining characteristic is its gaping, jawless mouth, which is filled with rows of tiny teeth ideal for hooking onto the flesh of prey—and feeding on unwitting victims’ blood.
Despite possessing such decidedly vampiric tendencies, lampreys have long been considered a culinary delicacy. But, Megan Gannon reports for Live Science, researchers have had little luck finding archaeological evidence of past lamprey feasts, as the animal’s skeleton and teeth are made out of cartilage and keratin—materials unlikely to endure the test of time. That’s why Alan Pipe, a senior archaeozoologist at the Museum of London Archaeology, was so pleasantly surprised when he happened upon a set of lamprey teeth while sifting through sediment from a medieval-era cesspit located near the English capital’s Mansion House tube station.
Prior to Pipe’s discovery, which he and his team dated to between 1270 and 1400 based on knowledge of when the cesspit was in use, archaeologists had only identified two sets of lamprey remains in the United Kingdom. One was found at Coppergate in York, England, while the other was spotted at Scotland’s Dundrennan Abbey.
“Almost everything we know about the popularity of lampreys in medieval England comes from historical accounts,” Pipe said in a statement. “It is incredibly exciting, after 33 years of studying animal remains, to finally identify traces of the elusive lamprey at the heart of the historic City of London, preserved in the water-logged ground near the Thames.”
Atlas Obscura’s Matthew Taub notes that lamprey was particularly popular amongst medieval Britain’s rich and powerful. Henry I, the youngest son of the first Norman king of England, William the Conqueror, died in 1135 after allegedly enjoying a “surfeit of lampreys” and contracting food poisoning. (It’s worth noting, however, that this legend is probably the apocryphal creation of chronicler Henry of Huntingdon.)
According to The Telegraph’s Emily Gosden, another English royal, King John—best known as the villain in Robin Hood and the man forced to sign the Magna Carta—supposedly inflicted a heavy fine on the city of Gloucester after it failed to deliver his traditional Christmas lamprey pie.
Gloucester was tasked with cooking the king or queen’s holiday treat until 1836, Lewis Smith writes for The Guardian. At that point, the once plentiful fish species had almost vanished from Britain’s rivers, largely driven away by rampant industrial pollution.
During the current queen’s reign, Gloucester has stepped back into its one-time role, delivering lamprey pie for Elizabeth II’s 1953 coronation, as well as the 25th and 50th years of her reign.
But in 2012, the year of Elizabeth’s Diamond Jubilee, Gloucester was forced to draw on lamprey imported from the United States’ Great Lakes, where the fish is so abundant that it’s considered an invasive pest.
Luckily for the Brits, lampreys have enjoyed a resurgence in recent years, popping up in rivers across the U.K. as water quality improves and man-made barriers are removed. Still, those hoping to cook their own homemade lamprey pie are out of luck: As The Telegraph’s Gosden reports, the fish is now a protected species, and illegally catching one could land you a multi-year jail stint.
For now, lamprey lovers hoping to satiate their appetite may want to check out the Medieval Cookbook’s trove of fishy dishes. Whether you’re looking for pickled lamprey, lamprey sauce or a lamprey bake, these recipes are sure to transport you back in time to a medieval feast. Just make sure the fish is prepared properly—or else you could end up like King Henry I.