Information flow in the Persian Empire

How did information flow in the Persian Empire? Reading Ezra and Esther gives me the impression that royal edicts quickly reached the farthest parts of the kingdom.

This is a case in which extra-biblical sources help us gain a better understanding of the biblical text. Since you mentioned the Persian Empire, I will concentrate on that particular period. In the ancient world the primary means of communication available to the king was the messenger, whose effectiveness was determined by the quality of the empire's roads.

1. Importance of Roads in the Ancient World: The Persian Royal Road system was one of the best in the ancient world. It connected main cities to provide security and supply the needs of the travelers. Those roads were important for several reasons.

First, national security depended on them. In a sense those roads were military roads, used by the king to protect the empire by helping to mobilize troops rapidly and safely. Whoever had control of the roads would also have military superiority. At intervals along the roads were storage centers where food and water were available for troops.

Second, commercial caravans used the road system to move goods from different parts of the world. Although there is not clear evidence that during the Persian period merchants traveled on the Royal Road, this was a common practice throughout the ancient Near East. Traders brought with them not only goods and materials, but also their culture, enriching the social life of the empire. The taxes collected from them strengthened the empire's economy. The roads provided some safety to the traders, and inns where they could rest.

Third, the roads united the main cities of the empire, making it possible for couriers to deliver their messages within a short period of time. This was extremely important in time of war and also in keeping the empire united. The king had to know what was taking place throughout the empire on a daily basis.

2. Efficiency of the Royal Communication System: In antiquity traveling was usually slow, particularly with large groups. Ezra's caravan took about three and a half months to travel from Babylon to Jerusalem, an average of about 10 miles a day (Ezra 7:9). Armies usually moved about 14 to 15 miles a day, thus taking a significant amount of time to reach their destination. However, messengers took significantly less time to deliver royal decrees and other types of information. It has been estimated that it took Persian couriers about nine days to cover the 1,500 miles of the Persian Royal Road. Couriers were not the only means of communication. There were two others.
Aural communication was done by a series of individuals placed on lookout posts along the Royal Road, who literally shouted the message to the person on the next lookout. Greek historians tell us that the Persians trained young people to develop loud speaking voices, and some of them became famous as loud speakers.

Persians also used fires on the top of mountains to transmit messages from the king. Visual signals were so effective that they made it possible for the king, who resided in Persepolis, to know on the same day what was happening in Asia Minor. Efficient and quick ways existed for sending important information from the capital to the rest of the empire.

3. Pony Express: Esther mentions the use of "mounted couriers, who rode fast horses especially bred for the king" (Esther 8:10, NIV; see also verse 14). According to Greek writers, impressed by the Persian royal postal system, the king constructed post stations at certain intervals along the Royal Road where new riders and relay horses were available to continue to carry the mail to its final destination. The system allowed for travel during the night. Herodotus claimed that "nothing stops these couriers from covering their allotted stage in the quickest possible time-neither snow, rain, heat, nor darkness. The first, at the end of his stage, passes the dispatch to the second, the second to the third, and so on along the line" (8. 98). That "nothing stops these couriers" is possibly an exaggeration, but it illustrates the fact that in the Persian world it was possible for the king to share and receive information from around the kingdom in a relatively short period of time.