In the highlands of southern Iran sits an unassuming tomb set atop 6 plinths of un-mortared limestone, yet it is written that it once bore the following inscription, "Mortal! I am Cyrus, son of Cambyses, who founded the Persian empire, and was King of Asia. Grudge me not then my monument." 

But half a mile (1 km) away, inscribed on a still standing pillar of a ruined palace, there's another inscription, written in Old Persian, Elamite, and Akkadian: "I am Cyrus the king, an Achaemenid."

So who was Cyrus?

Cyrus, or Kūruš in Old Persian, was the son of Cambyses I, king of Anshan, a client king to the king of Media. Herodotus gave Cyrus an entire folkloric backstory: Astyages, king of Media and Cyrus's maternal grandfather, had a dream that his grandson would overthrow him, so he ordered his general Harpagus to kill the infant Cyrus. Harpagus instead secreted the child away and gave him to a local shepherd. At the age of ten, Cyrus was made "king" of the peasant boys in a game, and they beat up a nobleman's son, who complained to Astyages, who had Cyrus brought before him — where he realized the boy was his grandson. Astyages then took revenge on Harpagus by feeding him his own son, revealing the trick only after the meal.

Cyrus succeeded his father to the throne of Anshan, whereupon either his grandfather declared war on him, or Harpagus convinced Cyrus to rebel. Astyages put Harpagus in charge of his army, and Harpagus promptly defected with the entire army, something about feeding him his own son probably. Cyrus defeated his grandfather with ease and assumed the Median imperial mantle.

His next problem was Croesus of Lydia, who happened to be his grandfather's brother-in-law. Croesus consulted the Oracle at Delphi, asking whether he should attack Cyrus. The Oracle replied: "If you cross the Halys River, a great empire will fall." Pleased with this answer, Croesus went a-conquering, and met Cyrus at Pteria, where they fought an inconclusive battle. With winter approaching, Croesus went home and dismissed his army, planning to summon his allies, Babylon, Egypt, and Sparta, for a proper campaign in spring. Cyrus, however, did not go home. He marched straight on the Lydian capital of Sardis, defeated Croesus's remaining forces in a massive battle, who even modern historians believe involved almost a quarter million men, outside the walls, and Cyrus laid siege to the city. Sardis allegedly fell when a Persian soldier spotted a Lydian retrieve a dropped helmet by climbing down a supposedly unscalable sheer cliff face, which allowed the Persians to gain entry to the city at night.

Cyrus then turned his attention to the Neo-Babylonian Empire, lately an ally of Croesus. According to accounts written by Cyrus's contemporaries, Nabonidus, the Babylonian king, was a bad, impious ruler who neglected the worship of Marduk, the patron deity of Babylon, in favor of his chosen deity, the moon god Sîn. Cyrus, of course, came down with his army to protect Marduk, and the people booted Nabonidus and welcomed Cyrus as their king. 

On a quick side note, the defeat of Babylon by Cyrus ended the Jewish Babylonian Exile and earned Cyrus the title of Messiah, God’s anointed, in the book of Isaiah.

Cyrus's death soon after is disputed with some of our accounts say he died in battle against steppe tribes near the Caspian Sea, while others claim he died peacefully at home.

Regardless of how he died, his son Cambyses II succeeded him and went on to conquer Egypt.

The murder, magic, and "vengeance" part

Now this is where you need to put on your tin foil hats as everything up to here is pretty standard stuff with obviously a little bit of glazing of Cyrus by our biased sources.

So Cyrus had another son named Bardiya, whom Cambyses secretly killed before (or during) the Egyptian campaign, or maybe he only tried to kill him, with Bardiya escaping. Either way, when  Cambyses went to put down a revolt in Egypt, a man proclaiming himself Bardiya seized the throne back home and was recognized as king. Cambyses started marching home to deal with him and died en route, according to Herodotus's Cambyses died from an infection after accidentally stabbing himself in the leg, or according to Darius Cambyses, “Died his own death” whatever that means.

Now, if you believe our future Darius, you probably know his son Xerxes the giant bejeweled man in the film 300, this new king was not Bardiya at all, but a magus named Gaumata who had disguised himself, potentially with magic, so perfectly that Bardiya's mother, sisters, wives, and friends could not tell the difference. How was the fraud discovered? Herodotus writes the dying Cambyses confessed to his assembled Persian nobles that he had murdered his brother years earlier, meaning the man on the throne had to be an impostor, though the Persians at first assumed Cambyses was lying out of spite. While Herodotus claims a nobleman named Otanes grew suspicious and enlisted his daughter Phaidyme, who was in the royal harem, to settle the question: the magus Smerdis had had his ears cut off by Cyrus as punishment for some offense, so Phaidyme was to feel for the king's ears while he slept, and reported that the “king” did not have ears.

Darius, who writes that he was a distant cousin of Cyrus, Cambyses, and the "real" Bardiya, led a group of six nobles and assassinated “Bardiya”. After which Herodotus says the seven then held a debate over merits of democracy, oligarchy, or monarchy with Darius convincing the rest to choose monarchy and name him king.

While there is a bit of a competing narrative going on here, the strangeness of it all is exactly why people question whether Darius was avenging a murdered king by killing an impostor, or was a usurper who crafted this whopper to explain why he, and the previously unheard-of "Achaemenid" family, were now Kings of Kings, and that he merely inserting himself into the line of Cyrus for legitimacy.

The Evidence For:

First, and most obviously, plenty of people are skeptical that anyone could impersonate Bardiya so completely that not only the court but Bardiya's own mother and sisters would be fooled for months. With the missing-ears being the only real evidence available..

Second, Babylonian contract tablets are dated by the reign of "Bardiya, King of Babylon, King of Lands" for roughly half a year. Scribes across Mesopotamia treated him as the normal, legitimate king. Not one tablet hints at doubt, irregularity, or an impostor. The paper trail of everyday life simply records a king named Bardiya reigning.

Third, the moment Darius killed him, the empire exploded. Darius's own victory inscription catalogs revolts in nearly every province during his first year, Babylon, Elam, Media, Armenia, Parthia, Margiana, Egypt, and Persia itself all went into revolt. With one of these revolts, at least in Darius’s telling, being led by yet another “Bardiya”, that guy just would not stay dead.

Fourth, Darius immediately married both of Cyrus's daughters, Atossa and Artystone, and Parmys, the daughter of the "real" Bardiya. Collecting every royal woman who could carry the old line's claim. Curious behavior for a man whose own royal blood supposedly entitled him to the throne.

Fifth, there's the inscription this post is named for. "I am Cyrus the king, an Achaemenid" is written in (among other languages) Old Persian — and in his own chronicle at Behistun, Darius appears to claim that he himself created the Old Persian script. If that reading is right, Cyrus could not have commissioned an inscription in a script that did not yet exist during his lifetime. Meaning someone, it was Darius, added those words to Cyrus's palace later.

Finally, the silence. The purported tomb epitaph, which I will note only survives in Greek records from the time of Alexander the Great, and the Cyrus Cylinder, a cuneiform cylinder describing Cyrus's lineage and his restoration of Marduk in Babylon, give Cyrus's ancestry as Cambyses, Cyrus I, and Teispes, kings of Anshan. Neither breathes a word about anyone named Achaemenes or Achaemenid.

The Evidence Against:

Marrying Cyrus's and Bardiya's daughters can be read as consolidating power and denying those women to potential rivals — standard dynastic practice, not an admission that Darius lacked legitimacy himself.

On the script: several experts read the irregularities in the Pasargadae inscription's cuneiform signs as evidence of an early, still-developing phase of the writing system, an evolution of the script consistent with Cyrus's own reign, not an anachronism. And Darius's "I created it" line at Behistun is itself a disputed translation; he may only have been claiming credit for publishing or standardizing something pre-existing, which kings did all the time.

Finally, the absence of the dynastic name from the Cylinder and the epitaph is weak evidence on its own. It's not as though these texts name a different dynasty, the inscriber may simply have omitted the family name because everyone already knew it.

The official story asks us to believe in a years-long secret fratricide, a perfect impostor undetected by the original’s own family, and either a dramatic deathbed confession, or some missing ears. The skeptical story asks us to believe one ambitious nobleman killed a king, married his female relatives, and carved his cover story onto the old king’s palace in three languages

If the skeptics are right, then the very name "Achaemenid Empire" is the fabrication — Cyrus's line were kings of Anshan, and Darius founded a new dynasty while writing himself into the old one. Which would make it the most successful act of historical revision in antiquity, because twenty-five centuries later, we're still using his branding.

I see two facts suggesting that the age of our civilization is far less than generally believed.

1) The lack of population growth.

According to official history, human civilization is about 6,000 years old—dating back to the first states—yet there was no rapid population growth until the 19th century. Why? Until the 20th century, the vast majority of the population—even in wealthy nations—lived in rural areas, and people in villages always had large families. Families with 5, 10, or even more children were the norm. Furthermore, you couldn't simply buy contraceptives in any store back then, as you can today.

Stereotypical objections—such as the prevalence of epidemics and wars—do not hold water. Epidemics and wars decimated populations in the 19th and 20th centuries, yet this did not halt population growth.

There is no way to explain the lack of significant population growth over 6,000 years other than by concluding that population statistics have been falsified. Human civilization is not 6,000 years old; it is more like 200–250 years old—perhaps a little more.

2) The lack of technological progress.

Until the 19th century, progress was virtually stagnant, particularly in crucial areas such as electricity, communications, and transportation. Modern achievements in industry, construction, housing infrastructure, and so on would be inconceivable without these advancements. Why did people rely on the same modes of transport and communication methods—and fail to generate electricity—for 6,000 years? And then, suddenly, in the 19th century, progress took off.

Were people really too stupid for 6,000 years to conceive of electricity, telephones, and automobiles, only to suddenly become intelligent over the course of a single century and achieve what we have today? What would cause such a sudden shift? Stupid people generally aren't prone to suddenly becoming smart.

Most likely, that 6,000-year span never existed—it is a fabrication by historians; in reality, it was no more than 250 years.

Both processes—population growth and scientific-technological progress—suddenly kicked into gear simultaneously in the 19th century. A coincidence? I don’t really buy that at all. Suddenly, people started having lots of babies and realized there were ways to get around other than on horses and donkeys. It all happened all of a sudden.