The long history of the letter-form, its general stability, and its utility for a range of purposes has long been recognized. A major turning-point, with a particular impact on the study of NT letters, was the discovery and publication from the end of the nineteenth century of thousands of letters on papyrus discovered in Egypt—a geographical restriction whose disadvantages are now becoming more obvious; from the rubbish heaps of small communities, these predominantly represent the ephemeral dealings of private and public life, letters to family and friends, commercial or legal documents, appeals to local officials, etc. Alongside the evidence that they offer for the language, vocabulary, and style of koinē Greek in the Hellenistic period, and for multiple aspects of daily life, they also illustrate the tradition-bound conventions of epistolary practice reproduced extensively in the mundane transactions of every level of society over several centuries. For a while, at least, they turned attention away from the letters of the literary élite, of Cicero, Pliny, or Seneca; in particular, they reinforced the immediacy of the Pauline letters and the consequent inappropriateness of treating them as repositories of a systematic theology (see Deissmann 1901, 1927). They did not, however, displace the tendency to turn, first, to the letters of Paul, and only then to the others in the NT.
This sudden wealth of resources prompted explorations of the origin and evolution of epistolary conventions. The letter originated in the oral address of the messenger/bearer, in Greek letters resulting in the distinctive third person and infinitive greeting formula, ‘A to B, greeting (chairein)’; although this appears only in Jas. 1: 1 and Acts 15: 23 among NT letters (cf. Acts 23: 26), it dominates Greek letters from the third century BCE to the third century CE, often with subtle modifications according to the context and the status of the parties (Exler 1923). Other epistolary formulae, particularly within the outer framework of the letter, together with a broadly consistent structure, remain equally stable, enabling detailed studies of particular types of letters, such as introductions, recommendations, or petitions, and of fixed phrases or devices within the letter, such as the health wish, thanksgivings, transitional formulae, greetings to other parties, and the closing ‘farewell’ (see esp. Exler 1923; White 1971, 1972a, 1972b; Kim 1974, 1975; Doty 1973).
Despite their distinctive greeting formula (‘grace to you and peace from God…’), Paul's letters do illustrate many of these conventions, and their identification has been used to expose the structure of his letters, the deliberate effect of the vocabulary and phraseology, and the expectations implicit in them, as well as to investigate questions such as the independence and integrity of Romans 16 (Gamble 1977). The most thorough attempt to locate the language, style, and strategy of the Pauline letters among the papyri letters of the period must be the Papyrologische Kommentare zum Neuen Testament, whose first volume is on Philemon (Arzt-Grabner 2003); this enterprise, in its emphasis on the search for parallels, can only complement more traditional exegetical analyses. However, even Philemon exceeds the normal restrictions of length imposed by the size of a sheet of papyrus—which, within the NT, could encompass only 2 or 3 John. Inevitably, beyond the use of standard formulae and modes of transition, the body of any letter is bound to be less convention-bound than the formulaic framework; in the case of the NT letters it is the extent of the body that most distinguishes them from the papyri letters with which they have been compared, and so an epistolary analysis can only begin to address their production or the way they were received. Concentration on the formal characteristics of the letter-genre leads to an unproductive separation between shape and content.