Exploring the reign of Persian king Cambyses II, particularly in the context of Darius' rise, offers insights into the potential dangers of absolute power concentrated in the hands of a single individual—and the profound consequences it had for those around him.

His brief reign, from 530 to 522 BCE, is often seen as an example of the excesses of power exercised without oversight or accountability. Son of Cyrus II, Cambyses II conquered Egypt in 525 BCE, founding the 27th dynasty. This conquest was marked by extreme brutality. Offended by the resistance of King Psammenitus, Cambyses II had his children humiliated and massacred, forcing them to march dressed as slaves with nooses around their necks. He also desecrated Egyptian tombs as an act of revenge.

But his ambition didn’t stop there. He launched three failed military expeditions against his neighbors. The first was abandoned when his Phoenician fleet refused to attack Carthage. The second ended in tragedy: attempting to conquer Ethiopia, Cambyses sent an army without preparation or supplies, forcing his soldiers to resort to cannibalism as reported by Herodotus. Finally, an army sent to attack the sanctuary of Ammon vanished in the desert, reportedly engulfed by a sandstorm, according to the Ammonians.

The end of Cambyses II’s reign is often described as being marked by erratic behavior and alleged madness. Amused by blaspheming local religious beliefs, he allegedly fatally wounded the Apis bull, a sacred Egyptian deity, and ordered the assassination of both his brother and sister.

The Greek historian Herodotus presents the conspiracy of the Seven, in which seven Persian nobles, including Darius, slaughtered the usurpers of the Persian throne which is presented as a founding moment that sparked political reflection. It is worth noting that shortly before his death, Cambyses II fell victim to a scheme orchestrated by one of his trusted men: following his brother's discreet assassination, since the population was unaware of his death, he replaced him with his own brother. Thus, this non-Persian individual became king after Cambyses II’s death and ruled as a usurper for several years.

After years of chaos and misfortune, the Persian nobility appears to have reflected on the best political system to restore Persian imperial power. They all agreed never again to submit to the rule of a single man who could act as he pleased without being held accountable. In any case, pride, the pursuit of personal gain, and reckless haste are flaws inherent in such a political situation.

Herodotus’s account of the 'conspiracy of the Seven' can be seen as highlighting a rare but valuable idea: that of decisive and discreet action. Unlike Cambyses II, portrayed as a madman driven by impulse, the six original conspirators acted with caution and discretion. Darius, the seventh, took the leadership role, convinced it would be dangerous to wait any longer—and even riskier to include more participants in the plot. He firmly believed that even acting as a group might feel reassuring but ultimately increases risks: the wider the circle, the more fragile the secrecy.

Action, to be effective, must be both slow and swift.