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This medieval king ruled a vast empire and inspired the pope. He also didn't exist

This medieval king ruled a vast empire and inspired the pope. He also didn't exist

Despite there being no evidence that he existed, belief in an impossibly powerful and wealthy ruler of a Christian empire in the east persisted for centuries and spurred on explorers

A medieval nautical map illustration depicting a ruler or figure in a tall hat and blue cloak, surrounded by walled cities, flags, and red rhumb lines

Jonny Wilkes

Published: October 18, 2026 at 11:30 AM

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In 1145, the German bishop Otto of Freising published his influential work of history and philosophy, the Chronica, in which he mentioned a Christian ruler of a domain far to the east. This priest-king had defeated the Muslims in battle and set out to capture Jerusalem, but had been unable to cross his army over the Tigris River.

This is the first-known written reference to Prester John, a significant figure in medieval Europe, despite the fact that he never existed.

The myth behind the man

Twenty years later, in 1165, a letter appeared at the court of the Byzantine emperor purporting to be from the mysterious man, the “supreme ruler of the three Indies”. In the lengthy missive, he introduced himself: “I, Prester John, am lord of lords and surpass, in all riches which are under the heaven, in virtue and in power, all the kings of the wide world.”

He was a devout Christian who served as both king and religious leader (the word ‘prester’ means priest) of a vast empire where 72 kingdoms lived in peace and all crime and vice had been eliminated. Riches abounded, with rivers literally flowing with precious gems, and mythical creatures such as the phoenix and cyclopes thrived.

Not only did the letter promise a Christian paradise on Earth that could be explored, but also the ally that Western Europe so badly needed to fight the Muslim forces in the crusades.

A detail from the 14th-century Catalan Atlas map depicting Marco Polo's caravan of pack camels and horseback riders traveling along a road marked with navigational rhumb lines

Marco Polo’s caravan travelling to India, from the Catalan Atlas, 14th century. Despite no evidence that Prester John existed, Polo referred to him as a real figure | Credit: Getty Images

Why did people believe Prester John was real?

The letter was a fake written by a still-unknown author, yet it was widely circulated. Soon, the name and reputation of Prester John spread across Europe with many having no problem in considering him to be completely genuine. Pope Alexander III even sent an envoy to attempt to deliver a letter to this imperious king to the east.

Europeans had long believed that there had to be Christian kingdoms in the east, and not without reason. There were indeed huge Christian communities across Asia; it was thought that Prester John – who claimed to be a descendent of one of the Magi, the three wise men who visited Christ at his birth – may have belonged to a sect called Nestorianism.

Read more | Alice Roberts: “Christianity didn’t invent itself as an empire from nothing: it adapted existing Roman structures”

Limited knowledge of geography beyond the Islamic world meant that Europeans simply did not know who lived there and what they were like, so why could there not be a Christian ruler of a vast empire? There were enough kernels of truth on which to grow Prester John’s image too: there were indeed non-Muslim peoples making their presence known in Europe, namely the Mongols.

Perhaps the most important factor in why Prester John’s existence was not questioned too strongly was that Europeans wanted to believe in him. They wanted to hold onto the possibility of an ally that would change the course of the crusades, to be evoked whenever the need was greatest.

Following the disaster of the Fifth Crusade, Jacques de Vitry, bishop of Ptolemais, wrote to the pope with words of optimism, explaining how the Muslims had been attacked by David, King of India and a descendent of Prester John. Historians have speculated that this account might have been inspired by Genghis Khan.

The move to Ethiopia

The story of Prester John inspired many travellers and missionaries over the years to head into the unknown and locate his near-magical kingdom, thought for some time to be in India. By the time Marco Polo went on his travels in the late 13th century nothing had been found, but he still referenced Prester John as a real figure in the region.

A historical black-and-white map of East Africa and the Arabian Peninsula, featuring illustrations of elephants, sailing ships, and decorative Latin text blocks

A 1573 map depicts Abyssinia – the area famous for being the mythical Christian empire of Prester John | Credit: Getty Images

As it became increasingly clear, however, that there was no Christian empire of the size and power related in Prester John’s letter, the story shifted to place the king in Africa instead, specifically in Ethiopia, where a Christian community had existed since the fourth century.

Read more | Do The Travels of Marco Polo belong in the non-fiction section, or fantasy?

From the 14th century, embassies from Ethiopia travelled to Italy and established a presence in Rome, and Europeans quickly jumped to the conclusion that their leader must be Prester John. Tales emerged of how his land contained the source of the Nile and he had the power to divert its course and wreak havoc in Egypt.

The Portuguese committed huge resources to their exploration of Africa – which led to Vaso da Gama’s world-changing voyage to India around the Cape of Good Hope from 1497-99 – fuelled in no small part by the aim of finding Prester John once and for all. They did find a Christian ruler in Ethiopia, but it was clear that this was not the all-powerful, fabulously wealthy king of the legend.

While belief in Prester John diminished, this mythical king had a very real legacy: it was the desire to find his empire that helped light the fires of European exploration in Asia and Africa.

Authors

Jonny WilkesFreelance writer

Jonny Wilkes is a former staff writer for BBC History Revealed, and he continues to write for both the magazine and HistoryExtra. He has BA in History from the University of York.