Letter‐writing arose in antiquity to serve official purposes. There were three broad types of official correspondence: royal or diplomatic letters, military orders and reports, and administrative correspondence used in managing internal affairs. Most letters embedded in the Hebrew Bible, along with several other nonbiblical Israelite and Jewish letters, are official in nature. Solomon's correspondence with King Hiram of Tyre, for example, is diplomatic (1 Kings 5.2–6, 8–9; see also 1 Kings 21.8–10; 2 Kings 10.1–6). The Lachish letters, written when Judah was under siege by Babylonia, are military communiqués. We may add to these the letter from the Jewish military settlement in Egypt at Elephantine, which was sent to the Persian governor of Judah, requesting his intervention against attacks on a Jewish temple.

Originally, messages were oral, carried by trusted couriers. With the passage of time, the principal message of the letter was delivered in written form, but the letter's sender continued to be identified orally by the messenger with the phrase, “Thus says …” (e.g., Ezra 1.1–2). A written message provided confirmation of the letter's authenticity, especially when signed with the sender's seal (1 Kings 21.8–10; Esther 8.10). The written message carried by Uriah from King David to the military commander Joab was clearly closed, because it commanded Uriah's own death (2 Sam. 11.14–15).

Though professional couriers were used by ancient states from the beginning of recorded history, the first organized postal system was not established until the sixth century BCE, when the Persian king Cyrus set up a network of highways and relay stations. This postal system served as a model for Alexander the Great and his successors, as well as for the Roman empire.

Even when the entirety of the letter was written, the messenger often continued to play a supplemental role. This was certainly the case with Paul, who usually employed trusted coworkers as couriers and who expected messengers to represent him to his correspondents (1 Cor. 4.17; 16.10–11; 2 Cor. 7.6–16; 8.16–18, 23–24; 12.18).

Various materials were used for written messages. Correspondence in Mesopotamia was written on clay tablets in cuneiform script by means of a reed with a wedge‐shaped tip. It was common in a number of places to write with a brush or reed pen on potsherds (ostraca). Parchment and vellum (skins) were used for more important correspondence. Papyrus was the most widely used material during the Persian and Greco‐Roman periods. When Hellenistic rulers proclaimed benefactions and edicts worthy of permanent record, they were inscribed on stone after delivery. (see Books; Writing in Antiquity.)

Gradually, the letter was adapted to serve personal and nonofficial purposes. We know from archaeological discoveries that, at least in Greco‐Roman Egypt, all levels of society sent letters. Although many were written by scribes, literacy was not as rare as was formerly believed. Nonetheless, ancient postal systems existed to serve only state business, not private correspondence. Whereas wealthy families and business firms could use employees or servants to carry their mail, ordinary people depended on those traveling on business (e.g., by ship or caravan) or on friends and passing strangers.

Greek and Roman rhetoricians regarded the cultivated letter of friendship as the most authentic form of correspondence. The letter was conceived as a substitute for the sender's actual presence. Since the recipient, however, could not ask for immediate clarification on epistolary subjects, it was recognized that the letter had to be more articulate than face‐to‐face talk. Despite the more studied style of letter‐writing relative to conversation, theorists warned that the discussion of technical subjects was not appropriate in a letter. Nonetheless, the democratization of knowledge in late antiquity, along with the dialogic character of popular philosophy at the time, made it almost inevitable that much philosophical and religious instruction would be communicated in epistolary form.

While none of the books of the Hebrew Bible takes the form of a letter, twenty‐one of the twenty‐seven New Testament books are letters (also known as “epistles”). This difference stems in part from the fact that New Testament letters were written by Greek‐speaking Jewish Christians who were influenced by the Hellenistic practice of writing instruction in the form of letters. Moreover, letters were often used by Christian leaders, such as Paul, to maintain contact with widely separated congregations.

The New Testament letters and patristic letters of the first three centuries CE are much longer than most pieces of ancient Greek correspondence. This length corresponds directly to their purpose as letters of instruction. In this respect, Christian letters are more like philosophical letters of instruction than like ordinary letters. On the other hand, the hortatory rhetoric used in Christian letters differs significantly from that in literary letters. For example, the emphasis on the whole community's spiritual maturation brought about by Christ's return, rather than on building one's individual character, shows that Christian letters were written by a specific religious subgroup with an apocalyptic Jewish coloring. Their special character is evident in the way traditional Jewish materials are cited within the letter (doxologies, benedictions, hymns), as well as in the tone of familiarity and equality that frequently described Christian recipients and their senders as family members. Later, in the fourth and fifth centuries CE, letters from Christian leaders conformed much more to Greek literary models of letters.

John L. White