The importance of succession planning in ancient kingdoms is illustrated by the riots that erupted in places like Alexandria when the general public felt ignored. Darius, who became the king of Persia after the ruler's death, ensured that the right successor was chosen, an important task in ensuring stability in any kingdom or empire.
In this episode, the focus is mainly on the instability brought by the successor of Darius as well as the importance of the empire's military in maintaining control of its vast territories.
The deaths of some of the greatest Persian kings such as Cyrus the Great and Darius remain shrouded in mystery as history doesn't record how they died. Some traditional stories associate their deaths with war and assassination, but the truth remains unclear.
The next Persian king after Darius was either Cyrus's other son and heir to the throne or some Magi from outside the royal line.