The accession of Darius the Great

Darius’s accession to the throne follows from a few major plot points. Firstly, that Cambyses, son of Cyrus and king of the empire, kills his brother Bardiya. Secondly, that the Magian Gaumata installs a monarch on the throne pretending to be Bardiya rebelling from Cambyses. Thirdly, that Cambyses dies. And fourthly, that the Persians retake the empire and Darius is installed as monarch.