Allowing local traditional local governments to continue, overseen by Persian provincial governors with king and council oversight.
Egypt and Libya were part of the Persian Empire.
Maintaining peace, security and prosparity.
Maintaining good and fair government, providing internal and external security, and maintaining prosperity and taxing fairly.
First by conquest, then by maintaining peace internally and providing protection externaliy.
Alexander the Great took effective control of the Empire in 331 BCE, so by 330 BCE there was no Persian Empire to rule - it was the Macedonian Empire of Alexander.
It was merely a Persian religious sect which did not have a political influence. The Persian Empire was divided into 20 provinces (satrapies) with a Persian governor (satrap), overseen by the king and his council, an entirely practical approach, not a religious one.
They divided it into 20 provinces (satrapies) with a Persian provincial governor (Satrap) in control supervised by the king and his council.
Local government by appointed tyrants/princelings, with provincial control by a Persian governor and overall control by the king and his council.
Local government, controlled by PERSIAN provincial governors with central control by the king and his council.
Indigenous local government, Persian provincial governors, and a central control by king and his council.
By retaining local government, with Persian provincial governors and a central control by the king and his council.
An attempt by the Persian Empire to bring the incessantly warring Greek city-states under its control to stop the fighting spilling over into the Persian Empire and damaging its peace and prosperity.