The Persian satrapal system — the division of the empire into provinces governed by satraps (governors), usually members of the royal family or high nobility — is one of the most important administrative innovations in ancient history.

The satrapy system combined significant delegated authority with mechanisms for central oversight that were genuinely sophisticated. Satraps had military, fiscal, and judicial authority within their territory. But royal secretaries kept independent records, royal treasurers controlled the financial surplus, and the king's eye (the basileus's personal inspector) could be sent at any time to review a satrap's conduct.

The system's weakness was succession: a satrap of sufficient military and financial capacity was always a potential rebel, and the history of the Achaemenid empire includes numerous satrapal revolts. The Satraps' Revolt of the 360s BC involved multiple satraps simultaneously in an uprising that came close to fracturing the empire. The mechanisms of oversight were imperfect checks on the centrifugal forces inherent in any large empire.

Alexander's adaptation of the satrapal system for his own empire was not simply adoption: he inserted Macedonian military commanders alongside Achaemenid administrative personnel in many satrapies, creating a dual administration that was unstable in practice. His successors gradually consolidated along lines that privileged either the military or the administrative side of this arrangement.