People tend to think of urban legends as a fully modern phenomenon, inextricably linked to 20th century ephemera like highway hitchhiking or teens being menaced at Makeout Creek. In point of fact, the subject matter isn’t what makes an urban legend, it’s the way the stories spread. We’re talking about stories transmitted primarily by word-of-mouth, reinforced by the implied trustworthiness of friend-of-a-friend corroboration.
Your cousin’s friend’s boss totally found an entire cow eyeball in his Big Mac, why would he lie about that? And why would a hundred generations of Europeans lie about the existence of a mighty Christian utopia ruled by an immortal priest-king?
The answer is that it’s not a lie, really, or at least not fundamentally. There could be many elements of the story that are patently untrue, but to the people who hear and repeat them, they have the air of plausibility, and they often seem to confirm the hopes and anxieties of the culture in which they spread.
Who Was Prester John?

John was the king and patriarch of a long-lost Christian kingdom, isolated from Europe by the Islamic world. Depending on who told the story and when, John’s kingdom was located either in India or in Africa, but it was always said to be fabulously wealthy and home to any number of natural and supernatural wonders. And the hook was that, with his mighty armies and incredible wealth, John would help Christian Europe finally and decisively conquer the Holy Land and establish a perfect, utopian kingdom in the church’s name.
In 1165 CE, a document appeared in Europe, supposedly written by John himself. In it, he described the many wonders of his home in India, and his desire to share his riches and wisdom with the Christians of Europe. You may recall that this never happened, largely because:
Prester John Was Made Up
Or more accurately, he (and his empire) were a relatively plausible conflation of known history, speculative geography, and poor demographic understanding of the world outside of Europe. Most significantly, resilient folk belief in a long-lost community of Christians somewhere beyond the frontiers of Europe was likely based on real history.
In 286 CE, the Roman Empire was divided into western and eastern halves. The Western half, comprising much of Europe, would fall apart two hundred years later, ushering in an age of decentralized chaos, but the eastern empire remained cohesive for way longer. This so-called Byzantine empire finally collapsed in 1453, meaning that Christianity had nearly ten centuries to ferment in a region of the world that had long since become alien to Europeans.
Even though the Byzantine empire would gradually cede territory to other regional powers, Christian missionaries continued to stream east, founding communities in Persia, Mongolia, China, and most significantly for the Prester John mythos, in India.
An Imaginary India

The India of the European imagination was probably more defined by its legendary features than by any actual geographic or demographic features. It was first described by the Greek writer Ctesias, who had worked as a physician in Persia. His book, Indica, is a collection of wild stories and half-remembered proto-Snapple Facts; while getting some things right, he also happily claims that the subcontinent is inhabited by unicorns, dog-faced men, and a tribe with feet large enough to be used as umbrellas (!!!).
In subsequent centuries, Europeans would encounter just enough of India to confirm that there were indeed unknown civilizations and mysterious cities there, but not enough to rule out the possibility that even wilder shit — dog-faced unicorns, etc. — could still exist there, and it kind of became a magnet for mystery. In the same way that modern paranormal or pseudohistorical discourse always seems to rope in Atlantis at some point, ancient bullshitters looking for a plausible location for wild tales often chose India. Where else would a mighty empire of secret Christians choose to set up shop?
In 1221, the French writer Jacques de Vitry returned to Europe from the 5th Crusade with great news: Prester John had finally struck out against the Saracens!
His great host, with his son David at its head, had finally left India to reclaim the Holy Land. David and his armies had already conquered Persia, and it was only a matter of time until the whole of Christendom would be reunited. If you don’t remember this happening, it’s because:
David was Actually Genghis Fucking Khan, Oops

As it happened, there was an irresistible military force disrupting centuries of Islamic rule in Asia, but he didn’t really give a shit about religion one way or another. The Khan’s ascendancy did mean that Europeans could now travel further into Asia than ever before, and in relative safety. Over subsequent centuries of gradually increasing familiarity, it became clear that there had never been a great, mystical Christian kingdom in Asia. Prester John had been a flight of fancy the whole time. Europeans gave up the search, chuckling at their own gullibility.
Just Kidding, They Decided He Lived in Africa
Ethiopia, technically, which Europeans once knew as one of “The Three Indias.” As you are no doubt aware, Ethiopia is fully NOT An India, which makes you better qualified to draw a map of the world than any European born before, like, 1500.
The logic this time went that because Ethiopia was a Christian kingdom that had survived the proliferation of Islam in North Africa, surely Prester John was in there somewhere. But in a truly ironic twist, when communication was finally established between Ethiopia and Europe, it was because the former was trying to request aid from the latter against Islamic expansion.
But by now, Europe had changed how it interacted with the outside world. Out with the Crusade and in with colonization, with slavery, with looting the priceless relics of the ancient world. With this change in priorities came stories about cities of gold and treasure-laden tombs; in effect, John was finally dead, but the spirit of his story lived on in the constant yearning for the mystery that lies so tantalizingly beyond the frontiers of the known world.
Here’s Johnny (Still)!
Despite having been debunked for over 500 years — and totally fictional for another 500 before that — Prester John is still around if you care to look for him. He’s mentioned in Shakespeare, if briefly. Charles Williams created a medieval folklore Reese’s flavor combination by making John the keeper of the Holy Grail in his novel War in Heaven. The good Prester would even fall victim to the same fate that befalls so many figures of the premodern imagination when he found himself forced to throw hands with the Fantastic Four in the pages of Marvel Comics.

Also my cousin Terry’s ex-wife’s hairdresser swears she saw him building one of those 5G coronavirus towers and it had a big Tesla logo on it, and she wouldn’t have any reason to lie about that.