How did the geography and the environment affect Persian Empire development?

It's progressive expansion/conquest of the various territories which were incorporated into the empire over a period of fifty years each brought new territory, new geography, new peoples, new customs and new challenges to government. The Persians coped with this by retaining traditional local government, with Persian provincial governors for overall control and protection. Economic development proceeded, communications between provinces were improved, a common language Aramaic was introduced for official communication, armies and fleets were levied as necessary from the provinces for defence.