CORRECTED POST Persian period times of messages
- Between the 5th century BCE and the mid-19th century CE, the fastest method of land transportation was the galloping horse, although chariots might have travelled faster for short distances.
For 18 months (April 1860 to Oct. 1861) a fast mail service known as the Pony Express operated in North America between St. Joseph, Missouri and Sacramento, California, a distance of nearly 3200 kms. Express riders galloped for about 25 kms, took a two minute break, then galloped off again on a fresh horse. Every 100 to 120 kms or so a fresh rider took over. Average speeds were a little more than 16 kms an hour, or some 400 kms a day. In this way the Pony Express covered the 3200 kms in eight to ten days, depending on weather and trail conditions. Not bad, considering the Express trail crossed the Rocky Mountains and passed through long stretches of hostile territory.
The Persians ran a highly organized empire. Had they chosen to do so, they could easily have operated "Pony Express" communications in the ANE. On flatter terrain, they probably could have sent news and messages at average speeds faster than those achieved by the Express. A lot would depend on just how urgent the news was. The death of Alexander would certainly have sent riders racing in all directions.