A Survey on the Duty and the Name of Immortal Army during Achaemenid Period Based on Historical and Linguistics Documents

One of the reasons for Achaemenid’s achievements in wars and administration of the state was the innovation and accurate organization in the administrative and military affairs. These organizations, in some cases, have originated in previous governments and Achaemenids had revolved them. Army units of Achaemenids are amongst these matters that somehow have originated in Ancient East and the aim of this article is to make clear the duty of Immortal Army based on works of ancient and contemporary writers and archeological documents while analyzing that whether the name Herodotus have imputed to them and have been rejected by some of the writers is correct or not. Beside these sources, linguistic references have been used also for better conclusion.