By the 6th Century BCE, the Persians had developed the largest Empire in the world, stretching from all the way from Modern-day Libya to Modern-day Pakistan.
In order to manage such a large Empire, people and cultures, the Persians innovated two new institutions:
1. Communication and Mail
2. Federalism
1. Communication and Mail: The Persians understood that effective authority over all this land will require fast communication between all parts of the Empire. A postal service was maintained by horse rising postal men, riding from one post to the other over a 1500 mile road, ensuring that messages across each part of the empire could reach within 1 week.
2. Federalism: The Empire was divided into smaller provinces and a local ruler, obedient of the Persian king, was chosen to rule over them. This meant that local people could live under their culture, religion and traditions while supremacy was held by the King.
These two factors were instrumental in the growth and management of the Persian Empire