It has long been known that there is a problem with the apparent chronological order of letters 90–110 of Book 10 of Pliny's Letters. These letters are set in the province of Pontus, which lay east of Pliny's other province, Bithynia. Pontus was a long, narrow region that stretched along the seacoast from Amastris in the west to Sinope, the capital, and on to Amisus in the east. From Amastris to Amisus along the coast-road was a distance of 280 miles. Pliny entered this area in the fall and travelled in it during the winter (Ep. 10.88 was written on the occasion of Trajan's birthday, 18 September, while Ep. 10.100 records New Year's vows). Four of the letters in the group (Ep. 10.90–110) have geographical references. In Ep. 10.90, Pliny is in Sinope dealing with the water supply; he has apparently just arrived (all previous letters are set in Bithynia). In Ep. 10.92 he is in Amisus handling the question of their benefit societies; in Ep. 10.98 he is then in Amastris, describing a plan to cover a filthy stream; and in Ep. 10.110 he is back in Amisus, dealing with donations.

As Sherwin-White remarked, ‘the order is odd’.Footnote ¹ The letters of Book 10 have traditionally been thought of as having been transmitted in the order in which they were written, ‘the contents of a file labelled “Emperor”’, to quote Coleman.Footnote ² From this point of view, the order of letters 90 to 110 presents a problem because, to read them as a literal record of Pliny's movements, we would have to suppose that the governor travelled the entire length of Pontus three times, covering over 800 miles, between late September and New Year's day. To avoid accepting this improbable travel program, Wilcken suggested that Pliny visited Amastris on the way to Sinope but deferred writing the letter (Ep. 10.98) because it was not pressing.Footnote ³ In response to this, Sherwin-White noted that the preceding Sinope letter (Ep. 10.92) appears equally unimportant; he suggested instead that Pliny was based in Sinope the whole time, presumably answering petitions from various cities.Footnote ⁴ But Pliny's description of the stream in Amastris (Ep. 10.98; see below) is vivid and suggests autopsy. Perhaps the ‘awkward’ arrangement of these letters (to quote Sherwin-White again) could be explained by a misfiling or inadvertent shuffling of the Pontic correspondence. But there is another potential explanation for the chronologically awkward letter: that it was deliberately placed where it is by the ancient editor of this book of Pliny's Letters in order to perform a specific function in the narrative formed by the sequence of letters, and particularly so that it would be read in close connection to the pair of letters immediately preceding it: the exchange regarding the Christians.

Ep. 10.96 contains Pliny's lengthy description of his interactions with people accused of being Christians. It concludes with a summary statement of how widespread the problem is: neque ciuitates tantum, sed uicos etiam atque agros superstitionis istius contagio peruagata est ‘It is not only the towns, but villages and rural districts too which are infected through contact with this wretched cult’, Ep. 10.96.9.Footnote ⁵ Christianity is described as a contagio, an infection or pollution that has spread everywhere in the province. Pliny goes on to claim that his actions (executing those who confess) have led to improvement but he, none the less, appeals to Trajan for further guidance. In his reply, Ep. 10.97, Trajan approves of Pliny's actions. He then recommends a course of action in dealing with Christians in the future: they should be punished when found (and the punishment for adherence to a superstitio was death), but Pliny should not seek them out. This is the context in which the reader encounters the next letter, Ep. 10.98, which reads:

The situation described by Pliny at Amastris in Ep. 10.98 has two connections to the pair of letters immediately preceding it, one to the problem of the Christians and another to the solution proposed by Trajan. First the problem: in Ep. 10.96 Pliny uses the metaphor contagio to describe the superstitio of the Christians; it is an illness or a pollution infecting countryside and the towns. In Ep. 10.98 this is echoed by Pliny's description of the polluted stream, whose smell is pestilens and which constitutes a threat to the salubritas of the city.Footnote ⁶ Both problems, the Christians and the open sewer, constitute a danger to the health of the community.

The second connection is found in the solution to the problems. Trajan's solution was to order Pliny that he should not seek out the Christians, but none the less that he should punish them if he came across any. In effect, the Christians were acknowledged as a serious problem, worthy of punishment if caught, but at the same time they were allowed to exist as long as they kept out of sight. Similarly the solution proposed by Pliny in Ep. 10.98 to the problem of the ‘filthy sewer’ is not designed to deal with the problem directly, for it will still exist beneath the pavement that Pliny proposes to construct, but rather to cover it up. Thus, it is possible to read Ep. 10.98 as a metaphor for the way in which the problem of the Christians had been handled. To prosecute Christians when discovered but not to seek them out was indeed a solution, but it was not a solution that dealt with the problem itself. The Christians would continue to exist, like the foul water in Amastris; they were merely covered up by the official position of not looking for them.

If we read Ep. 10.98 as a metaphor, there are two ways to interpret it. One is as implied criticism of Trajan's instruction. The apparent contradiction in Trajan's reply was mocked already in the second century: o sententiam necessitate confusam! (Tert. Apol. 2.7). But it is impossible to imagine Pliny, author of the Panegyricus, criticizing Trajan in public. The other interpretation is that an editor anticipated exactly such a reaction to Trajan's solution and positioned Ep. 10.98 in an attempt to mitigate negative reaction to it. Ep. 10.98 offered an opportunity to present an example of how a similar problem (pollution) had been (or more precisely would be) dealt with successfully using a similar method: covering it up. Just as there is no need to clean the polluted water flowing in a covered sewer, as every Roman would know, so there is no need to root out the contagion of Christianity. It is safe enough out of sight and out of mind.

If this suggestion—that an editor moved Ep. 10.98 from its proper chronological place in order to juxtapose it with Ep. 10.96 and 10.97—is correct, then the chronological problem mentioned at the beginning of this note is solved: the original order of Pliny's travel through Pontus was Amastris-Sinope-Amisus, west to east in a single journey; it is the letter that has moved, not Pliny. This conclusion may also have implications for our understanding of the composition, editorship and intent of Letters Book 10. Woolf has argued that the apparently well-composed beginning of Book 10 and the pattern of depicting both Pliny and Trajan in a good light indicate the work of an editor with a particular goal in mind.Footnote ⁷ Book 10, argued Woolf, ‘is an artfully constructed image of the good aristocrat in his province, and of the best of emperors in Rome’.Footnote ⁸ Noreña has suggested that Book 10 was published by Pliny in his lifetime with the aim of enhancing the image of both himself and Trajan; he adduces as a parallel the publication of the Panegyricus, which ‘suggests that Pliny was quite willing to employ “official” texts in the service of his own public self-representation, and it is not unreasonable to see Book 10 in the same light’.Footnote ⁹ Gibson and Morello have taken the literary approach even further in evaluating Book 10 as ‘the crowning resolution of sub-narratives and themes which have been developed throughout the earlier nine-book collection’ and presenting Pliny ‘on the Black Sea as not only a new and better prose Ovid, but a new and better Cicero’.Footnote ¹⁰ The transposition of Ep. 10.98–99, if indeed deliberate, supports these arguments in three ways. First, the chronological displacement of the pair of letters indicates the deliberate action of an editor. Second, the movement of these letters in order to exploit the metaphor of the covered sewer and to reinforce the correctness of Trajan's decision indicates a strong desire to enhance the reputation of the emperor. This then leads to a final point related to the editorship of the book. Would a friend or acquaintance of Pliny have been invested enough in these considerations to deliberately move this letter? Perhaps not. But it appears altogether plausible that Pliny himself, deeply moved by the affair of the Christians and perhaps still unsettled by Trajan's contradictory instruction, would have recognized the allusive value of Ep. 10.98. If so, this is further evidence of Pliny's own hand in editing Book 10 of his Letters.