The postal system is a system for transporting written documents typically enclosed in envelopes and also small packages containing other matter, around the world. Anything sent through the postal system is called mail or post.
In principle a postal service can be private or official. Restrictions are generally placed on private systems by governments. Since the 19th century national postal systems have generally been established as government monopolies with postage (tax) on the article prepaid.
Worldwide the most common method of prepaying the tax is by affixing a self-adhesive postage stamp; the much less common method is to use a postage-prepaid envelope. Franking is a method of creating postage-prepaid envelopes under licence using a special machine. They are used by companies with large mail programs such as banks and direct mail companies.
In 1998 the U.S. Postal Service authorised the first tests of a secure system of sending digital franks via the Internet to be printed out on a PC printer, obviating the necessity to license a dedicated franking machine and allowing companies with smaller mail programs to make use of the option. The service provided by the U.S. Postal Service in 2003 allows the franks to printed out on special adhesive-backed labels. The system is expected to be taken up over time by postal administrations right around the world.
The world-wide postal system comprising the individual national postal systems of the world's self-governing states is co-ordinated by the Universal Postal Union, which among other things sets international postage rates, defines standards for postage stamps and operates the system of International Reply Coupons.
Communication via written documents that an intermediary carries from one person or place to another almost certainly dates back almost to the invention of writing. The development of a formal postal system comes much later, however. 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.
The first credible claim for the development of a real postal system comes from Assyria, but the point of invention remains in question. The best documented claim (Xenophon) attributes the invention to 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 Saragon 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 next credible claimant to the title of first postal system is China. Claims concerning the origins of this mail system also conflict somewhat, but it is clear that an organized postal infrastructure is put in place during Qin Dynasty (221 BC-207 BC) and that is is substantially expanded during the subsequent Han Dynasty. The origins of a Chinese mail system may go back to the Zhou Dynasty (1122 BC - 256 BC), when Confucius (551 BC-479 BC) says "news of deeds travels faster than the mail." It may also build on a pre-existing messaging infrastructure started by the Shang Dynasty. Whatever its point of origin, the Chinese Postal Service has clear title to the world's oldest continuously operating mail system. Today's Chinese mail system is continuous with one that was probably formalized under the Qin Dynasty.
The first well documented postal service is that of Rome. Organised 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 rhedae with fast horses; additionally there was another, slower, service equipped with two-wheels carts (birolae) pulled by oxen. This service was reserved to the government's correspondence, another service for citizens was later added.
By the name of the stations in which mail was distributed and messengers' routes crossed, derives the latin name of mail, Posta (originally posata or pausata = place of rest) because in these stations messengers used to rest during their voyages. The english term "mail" is instead supposed coming from the Teutonic name for the bag used by messengers.
Another important postal service was created in the Islamic world by the caliph Moàvia; the service was called berid, by the name of the towers that were built in order to protect the roads by which couriers travelled.
Well before the Middle Ages and during them, carrier pigeons were used, taking advantage of a singular quality of this bird, that 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 that was freed and could reach his original nest.
Many religious orders had a private mail service, notably Cistercians's one connected more than 6,000 abbeys, monasteries and churches. The best organisation however was created by Teutonic Knights. The newly insitituted universities too had their private services, starting from Bologna (1158)
Popular illiteracy was accomodated 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. Von Thurn und 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 und 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.
Modern mail is usually organised by national services (that in recent times are increasingly being replaced by privately-owned companies), reciprocally interconnected by international regulations (some of which still in their original 18th-century form, many others of which are set out by the Universal Postal Union), organisations and agreements.
As noted above, usually the payment for the service is settled with the attachment of a pre-paid postage stamp; when the envelope or package to which the stamp or stamps are affixed is accepted into the mail by an officer or agent of the postal service the agent usually indicates by means of a cancellation that it is no longer valid for pre-payment of postage (the exceptions being when he neglects to do this, or for stamps that are pre-cancelled and thus do not require cancellation). Stamps are also object of a particular form of collecting called philately, and often their commercial value on this specific market becomes enormously greater that the printed one, even after use. Another form of collecting regards postcards, a document written on a single robust sheet of paper, usually decorated with photographic pictures or artistic drawings on one of the sides, and short messages on a small part of the other side, that also contained the space for the address. In strict philatelic usage, the postcard is to be distinguished from the postal card, which has a pre-printed postage on the card. The fact that this communication is visible by other than the receiver, often causes the messages to be written in jargons.
Mail is quite generally protected by the secret of correspondence (secretus epistulae), meaning that no letter or other document can be read by other than the receiver (under U.S. law, this only applies to First Class Mail). This right is usually guaranteed by most national constitutions, like the Mexican Constitution. Usually special procedures are required in case correspondence has to be, openly or discreetly, controlled by police. The operations of control of the private citizens' mail is called censorship and concerns social, political, legal aspects of the civil rights. While in most cases this censorship is exceptional, military censorship of mail, particularly of soldiers at the front, is routine and almost universally applied.
The use of mail is subject to common rules and a particular etiquette. After the discovery of new communicating systems and vehicles, mail lost most of its special charm in favour of more quickly connecting systems such as the telephone, and remained as a vehicle for commercial or formal documents. It is however still widely in use in more cultivated classes for personal communication; in particular, wedding invitations are always sent by mail.
In modern times, mainly in 20th century, mail has found an evolution in vehicles using newer technologies to deliver the documents, especially through the telephone network; these new vehicles include telegram, telex, fac-simile (fax), e-mail, short-message-service (sms). There have been methods which have combined mail and some of these newer methods, such as INTELPOST, which combined facsimile transmission with overnight delivery. These vehicles commonly use a mechanical or electro-mechanical standardised writing (typing), that on the one hand makes for more efficient communication, while on the other hand makes impossible characteristics and practices that traditionally were in conventional mail, such as calligraphy.
This epoch is undoubtedly mainly dominated by mechanical writing, with a general use of no more of half a dozen standard typographic fonts from standard keyboards. However, the increased use of typewritten or computer-printed letters for personal communication and the advent of e-mail, has sparked renewed interest in calligraphy, as a letter has become more of a "special event." Long before e-mail and computer-printed letters, however, decorated envelopes, rubber stamps and artistamps formed part of the medium of mail art.
The ordinary mail service was improved in 20th century with the use of planes for a quicker delivery (air mail). The first scheduled airmail service took place between the London suburbs of Hendon and Windsor on 9 September 1911. Some methods of airmail proved ineffective, however, including the United States Postal Service's experiment with guided missiles for international mail transport (external link).
Receipts services were made available in order to grant the sender a confirmation of effective delivery.
Letters are often studied as an example of literature, and also in biography in the case of a famous person. A portion of the New Testament of the Bible is composed of the Apostle Paul's epistles to Christian congregations in various parts of the Roman Empire. Other famous letters include: