After the invention of writing, communication among people came into existence. However, development of formal postal systems occurred much later. Ancient postal services are well documented in existing records of events. China, Egypt and Assyria had their own postal services in ancient times. While the Chinese and Egyptian services were confined to imperial/pharaonic court circles, in Assyria the service was open to the mercantile class.
The first documented use of an organized courier service for the diffusion of written documents occurred in Egypt, where Pharaohs used couriers for the diffusion of their decrees in the territory of the State (2400 B.C.). This practice certainly has roots in the much older practice of oral messaging and may have been built on a pre-existing infrastructure. The mail, mostly government dispatches, was carried from place to place by pedestrian postmen who traveled along the banks of the Nile, horse or horse-drawn wagon. Actual examples of letters from Ancient Egypt still exist nowadays. Letters in form of clay tablets bearing messages written in cuneiform (wedge-shaped) script have been found. It is known that Babylonia and Ancient Egypt exchanged missives related to their comercial exchanges.