How were ancient persian rulers chosen?
The guiding principle was that of inheritance: the rulership of the Persian people and later the Persian Empire passed from father to son (almost invariably the eldest son) unless a usurper interrupted the succession. This was a very rare occurrence; I think it happened only three times during the entire Achaemenid Dynasty from c.520-330BC (Darius I, II and III being the gentlemen in question – and the latter two were members of the royal family, not outsiders). Upon or shortly before the death of the old king, the new king would have his brothers executed (usually strangled) to avoid disputes over the succession (it is noteworthy that when this procedure was waived in the case of Cyrus the Younger, he led a rebellion against his brother Artaxerxes II). The king ruled for life. He was the fount of authority and justice, appointing satraps and other officials and administering the laws of the Medes and Persians (which were never allowed to be altered).
