 Darius's account, written at the Behistun Inscription, states that Cambyses II killed his own brother Bardiya, but that this murder was not known among the Iranian people.A would-be usurper named Gaumata came and lied to the people, stating he was Bardiya.The Iranians had grown rebellious against Cambyses's rule and on 11 March 522 BCE a revolt against Cambyses broke out in his absence.