Seven Achaemenid clans or seven Achaemenid houses were seven significant families that had key roles during the Achaemenid era. Only one of them had regnant pedigree.[1]
According to Herodotus, after the departure of Cambyses II for Egypt, the usurper Gaumata impersonated Bardiya (Smerdis), the younger brother of Cambyses, and became king. A group of seven Persian noblemen became suspicious of the false king and conspired to overthrow Gaumata. After the death of Gaumata, in a negotiation to determine the form of government, Otanes (Hutan) recommended a democratic government but his offer was not adopted and monarchy continued in Iran.[2]
The names of them were mentioned in Herodotus' Histories and the Behistun Inscription:
Arthur Emanuel Christensen the Danish historian and Iranologist, Herodotus was mistaken to say their main prominence was participation of them in murder of Gaumata. Also, the Parthians continued those formations.[3]