Patrocles’ Caspian Exploration Fraud (Patreon)

The Hellenistic Greek geographer, government official, and military officer Patrocles conducted two voyages of exploration in the Caspian Sea. His account of what he saw had a major influence on European geographers into the Middle Ages. The only problem is that most of the important stuff he reported was flat-out wrong. How he got to that point is an interesting mix of history and speculation, and the fallout of his false discoveries make a great RPG adventure.

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The Caspian Sea

Patrocles was an accomplished man. He was an officer and geographer in the army of Alexander the Great. After Alexander died in 323 B.C., his generals and bodyguards divided his empire up among themselves. Patrocles wound up in the court of Seleucus I, formerly one of Alexander’s generals and now ruler of the Seleucid Empire. It spanned Persia, Syria, and Mesopotamia. Patrocles was a senior and trusted official of Seleucus I and his successor, Antiochus I. It was during the joint rule of the two kings (292-281 B.C.) that Patrocles was ordered to conduct a periplus of the Caspian Sea.

The word periplus is used to refer both to a Greek voyage of exploration and to its product: a sort of proto-map. Classical Greece did not possess maps as we understand them. They didn’t draw overhead views of swaths of land that that depicted the literal spatial relationships of locations. Instead, they made written maps. “If you start from this port and keep the land on your right, after two days you’ll come to the mouth of this river. After one more day, you’ll come to this other port.” When used to refer to a document, a periplus is essentially a list of places of interest in the order you encounter them. In a world where ships rarely left sight of land, a list of landmarks is more useful for navigation than a drawing of an imagined overhead view.

Patrocles wrote a periplus document, but it’s unclear to what extent he conducted a periplus voyage because his document is flat-out wrong. Most notably, it explains that the Caspian is connected to the northern ocean. That’s just not true. The Caspian is a saltwater lake, unconnected to any other saltwater bodies. Anyone who actually sailed the length of its coastline (as Patrocles’ periplus document claims he did) would know that. Moreover, this claim ran counter to the accepted wisdom at the time. Herodotus, Aristotle, and the historians and geographers of Alexander all describe the Caspian as an isolated saltwater lake. But many (though not all) later European geographers repeated Patrocles’ claim clear into the Middle Ages. This dude’s fraudulent voyage of exploration impacted Europe’s understanding of the Caspian for over a thousand years – even though the sea isn’t really that far from Europe.

This is a facsimile of part of the Tabula Peutingeriana, itself a 13th-century copy of a map made from a Roman road itinerary (which was structured much like a periplus). The blue at the top is the Arctic Ocean, while the blue below it is the Caspian. Note that the two are connected by a strait.

Patrocles’ description of his travels do not survive. We have to rely on later authors who repeated his claims. It seems he made two voyages, both from the southwestern corner of the Caspian. The first went north, the second east. On the eastern voyage, he claimed to have seen the mouths of the Amu Darya (Oxus) and Syr Darya (Jaxartes) rivers, which empty into the Caspian 250 miles apart. Patrocles also said the Amu Darya was navigable clear up to the Hindu Kush, which would make possible a water-only trade route with India. In reality, the two great rivers of Central Asia empty into the Aral Sea, never get anywhere close to the Caspian, and are certainly not navigable clear up to India.

The most charitable interpretation I could find of Patrocles’ falsehoods was that he only sailed a little ways on each voyage and augmented his report with testimony from people he met along the way. At the time of his voyages, he held some sort of military command in Central Asia. He might have just been too busy to carry out the full trip. Faulty translations might have informed him of the existence of the Aral Sea – a sea to the north (-ish) into which the Amu Darya and Syr Darya flowed – but not explained that the Aral Sea connected to neither the Caspian nor the northern ocean. Or Patrocles’ translators may have even gotten the broad strokes right, but later authors – upon whom we must rely – reframed Patrocles’ reporting in a way favorable to their (incorrect) ideas. A less charitable, more postmodern interpretation is that Patrocles was more interested in legitimizing the authority and delimiting the reach of King Antiochus I, and that the literal truth of his voyages were of secondary importance. And there’s also the possibility he just made it all up because c’mon. Who was going to go and check?

The Amu Darya flowing into what little remains of the modern Aral Sea.

At your table, a periplus that is not yet known to be fraudulent is a fantastic adventure hook. The voyage is far enough in the past that all the sailors are dead. But someone – a queen, a merchant, a space governor, or whomever – wants more information about one specific detail in the periplus. Maybe she’s planning a trade mission to a distant and wealthy land that the periplus says is reachable via a river that definitely enters this sea so-and-so many days in that direction. The sponsor doesn’t want the PCs to go all the way upriver to your version of India. (That would be a whole campaign and I’m interested in more limited adventures.) She just wants them to sail to the mouth of the river and make sure it hasn’t silted in or been blockaded by a foreign power. You can throw a run-in with a kraken or a malicious sea shanty at the party on the way there – but when they arrive, there’s no river.

The next phase of the adventure is figuring out what happened. Is the river farther down the coast? Did it move? PCs might sail a few days farther or land and talk to the locals. Of course in the process, they get caught up in some misunderstanding or have to save a village from a minor threat. But eventually they will have to conclude that not only is there not a river here, there never was.

The final phase of the adventure is figuring out what to do about it. If they return home and say “Patrocles was a liar”, your version of Patrocles (a powerful government official) will surely have descendants in positions of authority who will discredit the PCs and cause trouble for them. With a little luck, one of these folks might even become a recurring minor villain. On the other hand, if the party comes back, shrugs, and evades with a “Aw shucks, m’lady. Dunno what happened” then they look incompetent and may be accused of wasting their patron’s money. It’s a sticky situation to navigate!

Alternately, you can use this as an encounter while traveling instead of an outright adventure hook. Your PCs might meet some explorers going through exactly the sequence laid out above. These poor schmucks are searching for a river mouth they’re absolutely certain is around here somewhere. Look! They have this old report that says its definitely here! How do the PCs handle the situation?

Sources:

The Land of the Elephant Kings: Space, Territory, and Ideology in the Seleucid Empire by Paul J. Komsin (2014)

Patrocles and the Oxo-Caspian Trade Route by W. W. Tarn (1901)

And thanks to Reddit user udreaudsurarea on AskHistorians for introducing me to Patrocles!