One of the earliest and most effective mass communications system ever developed was the “kalliu” relay system of the Neo Assyrian Empire in the Middle East. The Assyrians formed one of history’s first empires in the 10th millennium B.C.E., perfecting many strategies and institutional of imperial rule that set the standard for other empires. Chief among these was their mass relay system, which allowed the empire to span 540,000 square miles and last over 300 years.
Rather than have one trusted envoy to deliver a message through a direct route, Assyrian rulers relied on multiple riders to stop at purpose-built stations where they would pass the message to another rider who was ready with a fresh mount. The stations were carefully positioned at regular intervals along the imperial highway system. Mules were used for their sturdiness and speed in rough terrain and climates. The system was maintained by the military and used only by the state: about 150 officials known as “Great Ones” held a copy of the Assyrian royal seal — depicting the king fighting a lion — which they stamped on messages to identify their authority, since it was recognized throughout the empire. Only letters with this seal could be mailed.
Because messages did not require one rider who would need to rest, the kalliu system offered unprecedented communication speed at the time. One estimate suggests that a message traversing 430 miles through rough terrain would take less than five days. Little wonder that later empires like the Persians adopted this technique for their massive territory. Even the United States used it as the basis for the famed Pony Express in the 19th century. Indeed, the use of a series of anonymous messages along different relay systems remain the basis of modern postal systems worldwide — to think it all began with an Iron Age Mesopotamian state nearly 3,000 years ago.