Many early post systems consisted of fixed courier routes. Here, a post house on a postal route in 19th century Eastern Europe

The art of communication by written documents carried by an intermediary from one person or place to another almost certainly dates back nearly to the invention of writing. However, development of formal postal systems occurred much later. The first documented use of an organized courier service for the diffusion of written documents is in Egypt, where Pharaohs used couriers for the diffusion of their decrees in the territory of the State (2400 BC). This practice almost certainly has roots in the much older practice of oral messaging and may have been built on a pre-existing infrastructure.

Persia

The first credible claim for the development of a real postal system comes from Ancient Persia but the point of invention remains in question. The best documented claim (Xenophon) attributes the invention to the Persian King Cyrus the Great (550 BC), while other writers credit his successor Darius I of Persia (521 BC). Other sources claim much earlier dates for an Assyrian postal system, with credit given to Hammurabi (1700 BC) and Sargon II (722 BC). Mail may not have been the primary mission of this postal service, however. The role of the system as an intelligence gathering apparatus is well documented, and the service was (later) called angariae, a term that in time turned to indicate a tax system. The Old Testament (Esther, VIII) makes mention of this system: Ahasuerus, king of Medes, used couriers for communicating his decisions.

The Persian system worked on stations (called Chapar-Khane), where the message carrier (called Chapar) would ride to the next post, whereupon he would swap his horse with a fresh one, for maximum performance and delivery speed. Herodotus described the system in this way: "It is said that as many days as there are in the whole journey, so many are the men and horses that stand along the road, each horse and man at the interval of a day’s journey; and these are stayed neither by snow nor rain nor heat nor darkness from accomplishing their appointed course with all speed".

South Asia

The use of the Scinde Dawk adhesive stamps to signify the prepayment of postage began on 1 July 1852 in the Scinde/Sindh district, as part of a comprehensive reform of the district's postal system.

The economic growth and political stability under the Mauryan empire (322–185 BC) saw the development of impressive civil infrastructure in ancient India. The Mauryans developed early Indian mail service as well as public wells, rest houses and other facilities for the common public. Common chariots called Dagana were sometimes used as mail chariots in ancient India.

Systems for collecting information and revenue data from the provinces are mentioned in Chanakya's Arthashastra (ca. 3rd century BC).

In ancient times the kings, emperors, rulers, zamindars or the feudal lords protected their land through the intelligence services of specially trained police or military agencies and courier services to convey and obtain information through runners, messengers and even through pigeons. The chief of the secret service, known as the postmaster, maintained the lines of communication ... The people used to send letters to [their] distant relatives through their friends or neighbors.

Early stamps of India were watermarked with an elephant's head.

In South India, the Wodeyar dynasty (1399 - 1947) of the Kingdom of Mysore used mail service for espionage purposes thereby acquiring knowledge related to matters that took place at great distances.

By the end of the Eighteenth century the postal system in India had reached impressive levels of efficiency. According to British national Thomas Broughton, the Maharaja of Jodhpur sent daily offerings of fresh flowers from his capital to Nathadvara (320 km) and they arrived in time for the first religious Darshan at sunrise. Later this system underwent complete modernization when the British Raj established its full control over India. The Post Office Act XVII of 1837 provided that the Governor-General of India in Council had the exclusive right of conveying letters by post for hire within the territories of the East India Company. The mails were available to certain officials without charge, which became a controversial privilege as the years passed. On this basis the Indian Post Office was established on October 1, 1837.

China

China 4-cent on 100-dollar silver overprint of 1949

China enjoyed postal relay stations since the Han dynasty (206 BC-220 AD). During the Yuan Dynasty under Kublai Khan, China was integrated into the much larger Örtöö system of the Mongol Empire.

Rome

The first well documented postal service is that of Rome. Organized at the time of Augustus Caesar (62 BC–AD 14), it may also be the first true mail service. The service was called cursus publicus and was provided with light carriages called rhedæ with fast horses. Additionally, there was another slower service equipped with two-wheeled carts (birolæ) pulled by oxen. This service was reserved to government correspondence. Another service for citizens was later added.

Mongol Empire

Genghis Khan installed an empire-wide messenger and postal station system named Örtöö within the Mongol Empire. During the Yuan Dynasty under Kublai Khan, this system also covered the territory of China. Postal stations were used not only for the transmission and delivery of official mail, but were also available for traveling officials, military men, and foreign dignitaries. These stations aided and facilitated the transport of foreign and domestic tribute, and trade in general. By the end of Kublai Khan's rule there were more than 1400 postal stations in China alone, which in turn had at their disposal about 50000 horses, 1400 oxen, 6700 mules, 400 carts, 6000 boats, over 200 dogs and 1150 sheep.

The stations were 15 to 40 miles apart and had reliable attendants working for the mail service. Foreign observers, such as Marco Polo have attested to the efficiency of this early postal system.

Other systems

Another important postal service was created in the Islamic world by the caliph Mu'awiyya; the service was called barid, by the name of the towers built to protect the roads by which couriers travelled.

Well before the Middle Ages and during them, homing pigeons were used for pigeon post, taking advantage of a singular quality of this bird, which when taken far from its nest is able to find his way home due to a particularly developed sense of orientation. Messages were then tied around the legs of the pigeon, which was freed and could reach his original nest.

Mail has been transported by quite a few other methods throughout history, including dogsled, balloon, rocket, mule, pneumatic tubes and even submarine.

Charlemagne extended to the whole territory of his empire the system used by Franks in northern Gaul, and connected this service with the service of missi dominici.

Many religious orders had a private mail service, notably Cistercians' one connected more than 6,000 abbeys, monasteries and churches. The best organization however was created by the Knights Templar. The newly instituted universities too had their private services, starting from Bologna (1158).

Popular illiteracy was accommodated through the service of scribes. Illiterates who needed to communicate dictated their messages to a scribe, another profession now quite generally disappeared.

In 1505, Holy Roman Emperor Maximilian I established a postal system in the Empire, appointing Franz von Thurn und Taxis to run it. The Thurn and Taxis family, then known as Tassis, had operated postal services between Italian city states from 1290 onwards. Following the abolition of the Empire in 1806 the Thurn and Taxis postal system continued as a private organisation, continuing to exist into the postage stamp era before finally being absorbed into the postal system of the new German Empire after 1871.

It was around this time nationalization and centralization of most postal systems took place. Today, the study of mail systems is known as postal history.