Darius I and the satrapies

Darius comes to power out of turmoil and within a year subdues the rebellious provinces. He divides the empire into some twenty satrapies — where governor, tax collector and garrison commander are deliberately kept separate — introduces a single coin, the gold daric, and lays the Royal Road from Susa to Sardis, along which couriers travel in a week instead of three months. Administration is conducted in Aramaic, understood from Egypt to the Indus; the same language sounds in the Jewish documents from Elephantine and in the Aramaic chapters of the Tanakh. This order will outlive the Achaemenids and become the model for the Hellenistic kingdoms and Rome.