What was the most profitable lie ever told in history?

The lie that made a man the ruler of a third or quarter of humankind.

Darius the Great (r. 522–486 BC) governed the Achaemenid Empire at its peak. His rule extended from the Indus valley to mainland Greece and from the Scythian steppes to Egypt. A remarkably high and possibly unparalleled percentage of the world population were his subjects. Darius reorganized the satrapies, which made the administrative system of his empire more efficient, and introduced major financial reforms as well.

It was never a secret that Darius became the King of Kings after a successful coup. He and a small group of other aristocrats (primary sources refer to seven men in total) infiltrated the residence of the previous ruler and killed him after a brief clash with his guards. Shortly afterwards, Darius, who was also a member of the royal house, emerged as the leader of the conspirators and assumed full power.

So far so good. Things become strange when it comes to the identity of Darius’ predecessor.

As far as the primary sources are concerned, Cyrus the Great (r. 559–530 BC) had two sons: Cambyses (r. 530–522 BC) and Bardiya. The former succeeded him as King of Kings, while the latter was given governorship over the eastern provinces. Fearful of opposition, Cambyses had his brother assassinated, but kept it a secret. Then he undertook the campaign that ended up bringing Egypt into the Persian fold.

While Cambyses was in Egypt, he started acting cruelly and erratically: suspected everyone, disrespected the local traditions and the sort. Then a rebellion broke out back in Persia led by a magus (Zoroastrian priest) named Gaumata. The man claimed to be Bardiya, and the people, ignorant of the latter’s death, flocked to his banner. It also helped that he took short-term populist measures such as tax cuts.

Cambyses rushed home to quell the revolt, but died on the journey. His death was listed as an accident or even a suicide out of desperation for the usurpation. Gaumata got to rule as Bardiya and even took over the latter’s harem. Almost nobody suspected he was an impostor, because on top of everything else he also bore an uncanny physical resemblance to the dead prince.

The first man to suspect something was off was a nobleman named Otanes, who would later become one of Darius’ six companions. Otanes knew about Gaumata’s existence and was also aware that at some point his ears had been cut off as a punishment. So he asked his daughter, who was Bardiya’s (and now Gaumata’s) wife, to check his ears while he slept. The truth was brought to the light.

Needless to say, the story was very convenient for Darius. By killing Gaumata, he saved the empire from a fraudulent, cunning and ruthless liar who had gone as far as to assume a dead man’s identity and risk civil war in order to take the throne for himself. Darius simply punished him for his crimes and reinstated the royal office to the house it belonged to: the Achaemenid dynasty.

But what if the whole story was a lie? What if there was no Gaumata, and the man Darius killed was the real Bardiya?

Indeed, scholars have noticed a lot of problems with the traditional narrative, apart from its convenience. How could the real Bardiya’s death be kept secret for so long from everyone except a simple magus — and what for? How likely is it that Bardiya had a doppelganger that had also the knowledge, courage and brains necessary to take his place at the right moment? And how is it possible that not even Bardiya’s wives and inner circle were able to see through Gaumata’s lies?

Some scholars go as far as to suspect that Cambyses’ madness might have been the product of Darius’ propaganda. Herodotus, for example, narrates that the King looted Egyptian temples, insulted the local gods and even killed the sacred bull Apis. The problem is, none of that appears in any contemporary Egyptian source — in fact, there are inscriptions showing that Cambyses honored the bull that died in 524 BC with a rich sarcophagus.

If things were so, it cannot be excluded that Cambyses was also assassinated by Darius, who we know served as his spear-bearer. His death might have prompted his brother Bardiya to take power, since Cambyses was childless. Darius proceeded to eliminate him too and then created the lie about Gaumata. Of course, it cannot be excluded that Bardiya did indeed rebel against Cambyses — that doesn’t change the crux of the matter, which is the story about Gaumata.

So there you have it. One of the most powerful monarchs of antiquity and a possible lie that went unquestioned for millennia by almost everyone.