1. This sentence appears in almost all the manuscripts as though it were the final sentence of Letter Twelve. However, as Hackforth correctly acknowledged, “There seems to be no means of deciding whether the note . . . belongs to xii or xiii” (1913, 163). That is, the manner in which early copies of the Letters were transcribed would have made it difficult for copyists to discern where the line belonged, so that the text of even our oldest manuscripts is more likely to reflect the best guesses of some earlier editors than anything else. For his part, Hackforth notes his agreement with Burnet that the line should be appended to the end of Letter Twelve, “because it is very much more natural to suspect xii to be spurious than xiii” (163). But this judgment is fundamentally debatable. Ficino (1484), Cudworth (1678), and Bentley (1838, 409–13), though they differed on the question of authenticity, all took the line as referring to Letter Thirteen. In any case, while this note is at least as old as the ninth century, it must be stressed that we have no way of knowing precisely when it was added to the manuscripts. We cannot say whether the doubt, to which this note attests, regarding the authenticity of Letter Twelve or Thirteen arose among Plato’s near contemporaries or more than a thousand years later (see, e.g., Burnyeat and Frede 2015, 6).

Vastly underconsidered, however, is the possibility that this line is itself an authentic part of the original Letters. If we are to entertain the hypothesis that the Letters is a unitary work of Platonic political philosophy—one that bears as a motif an “obsessive concern with [its] own authenticity” (Wohl 1998, 84), and more than once enigmatically seems to deny the genuine Platonic authorship of Plato’s writings—we should recognize that it would not be out of place for its author to have set this riddling line at the head of Letter Thirteen in particular: of all the letters in this collection, Letter Thirteen is the most explicitly concerned with its own genuineness (360a3ff., 363b1–6). In any case, there is every bit as much reason to believe the note may attach to Letter Thirteen as to Letter Twelve, regardless of one’s position on the status of the Letters in the Platonic corpus. I have placed it here in accordance with my own best guess.

2. The word “token” translates sumbolon—the origin of the English “symbol”—a word that appears here, at 363b1 below, and nowhere else in the Letters (but cf. n. 31 below). Sumbola were originally used as a means of confirming the identity of two contracting parties or their representatives. Upon their agreement, the parties would break an item in two and each take one piece as a sumbolon, which could thereafter be presented, say by a messenger or representative, to prove that the message in fact came from the other party. The word thereafter came to refer also to other means of proving authenticity (such as wax seals and certain kinds of identity tokens), and could sometimes refer to a prearranged “secret signal” or “password.” One should consider especially Plato’s use of the word at 363b1 below.

3. Locris was a Greek city on the Italian mainland with several points of connection to Plato and the Syracusan story of the Letters. Dionysius the Younger’s mother, Doris, was from Locris (Plutarch, Dion 3, 6), as was the physician Philistion apparently referred to in Letter Two above (314e3; see n. 57 to Letter Two)—this Philistion, moreover, was among the teachers of Eudoxus, mentioned just below, who also studied with Archytas and eventually, as it seems, with Plato at the Academy (see n. 9 below). It should also be noted that the Platonic character Timaeus, of the Timaeus and Critias, is said to be from Locris (Timaeus 20a1–3; cf. Laws 638a7–b3).

4. Presumably these “things” are texts; but Plato’s vagueness here is of a piece with a pattern throughout the Letters according to which he often uses an unspecified neuter plural to refer to doctrines, ideas, or other intellectual products of a school of thought, both his own and others’. See n. 44 to Letter Two.

5. This is the only explicit reference to Pythagoras in the Letters; implicitly, however, Pythagoreanism has been present in the Letters in the figure of Archytas, who is well known to have fostered a Pythagorean philosophic circle in Tarentum (see n. 86 to Letter Seven). Since the nineteenth century if not earlier, it has been speculated that the “Pythagorean things” to which Plato refers here would include Plato’s Timaeus and that the “divisions” (diaireseōn) would include Platonic dialogues such as the Sophist and Statesman, wherein the Eleatic Stranger—a follower of Parmenides, who stood at the head of the other great Italian philosophic school in this day—demonstrates his technique of discovering definitions by dividing the whole through “dichotomies.” See the notes of Souilhé, Harward, and Morrow ad loc.

6. On Archytas, see n. 86 to Letter Seven.

7. The only other extant reference to this Helicon is in Plutarch’s Life of Dion (19.4). There he is said to have been a man close to Plato (a sunēthēs) who so impressed Dionysius the Younger by predicting a solar eclipse that the tyrant awarded him a talent of silver.

8. Or “his tribe” (genos); see n. 8 to Letter Seven.

9. Eudoxus has been described as “the greatest of the classical Greek mathematicians and second only to Archimedes in all antiquity” (Kline 1972, 48). For discussions of his breakthroughs in geometry, astronomy, and medicine, see van der Waerden 1961, 179–89; on his moral philosophy, see also Aristotle, Nicomachean Ethics 1172b9–35. He is said to have been taught by Archytas (see n. 86 to Letter Seven) and Philistion (see n. 57 to Letter Two), and to have been a student and companion of Plato (Diogenes Laertius 8.8.86; Strabo 17.29; Proclus, On Euclid 67.2–3), and he was renowned for giving laws for his native Cnidus (Diogenes Laertius 8.8.88; Plutarch, Adversus Colotem 32).

10. Lit. “altogether graceful” (panu charientōs echōn).

11. I.e., his teachings, doctrines, or philosophy; see n. 4 above and n. 44 to Letter Two.

12. Isocrates (436–338 BCE), a contemporary of Plato, was an enormously famous and successful Athenian teacher who wrote and published an unusual variety of political philosophic texts. In Plato’s Phaedrus, the young Isocrates is said to be a companion of Socrates, who has high praise for him (278e4–279b3). The resemblance of Plato’s Letter Seven to Isocrates’s Antidosis—both being autobiographical and apologetic works, employing elaborate literary framing devices, and written toward the end of their authors’ lives—has been noted and should be considered (Post 1925, 58–61; Morrow 1962, 50–52; Harward 1932, 197).

13. On Polyxenus, see n. 5 to Letter Two.

14. Little is known of Bryson of Heraclea. He is criticized a few times by Aristotle for his “eristic” attempt to solve the geometric problem of squaring the circle (Posterior Analytics 75b40–76a3; Sophistical Refutations 171b16–172a7) and for his argument that there is no such thing as the use of foul language (Rhetoric 1405b6–16).

15. “Of bad character” and “of good character” are here literal translations of the antonyms kakoēthēs and euēthēs. The words have further connotations that should be considered. The former may mean especially “malicious,” and the latter often carries the negative meaning “naive” or “simpleminded.” Likewise, elaphros, literally “lightweight” and here rendered “easygoing,” can also mean “simpleminded,” but could also be translated “lighthearted” or “cheerful.” The word appeared in Letter Two above, where it was translated “easy” (314e5).

16. This Leptines (who is not to be confused with his father of the same name, brother to Dionysius the Elder), though mentioned in none of Plato’s other letters, is evidently the one who is to convey this letter—or, at least, the gifts mentioned in this letter—to Dionysius, and it seems throughout this letter that both Plato and Dionysius consider him a trustworthy associate; in this respect, he performs the function here in Letter Thirteen that Archedemus did in Letter Two (see n. 1 to Letter Two). It has often been presumed, with reasonable cause, that this is the same man mentioned by Iamblichus as a Pythagorean from Syracuse (Vita Pythagorica 267). Certainly, this would seem to be the same Leptines who Diodorus Siculus says ruled Syracuse together with Dion’s murderer Callippus (16.45.9), and who Plutarch claims later assassinated Callippus (Dion 57.6).

17. Leochares, who would indeed still have been a “young craftsman” at the time of this letter, “became a sculptor of scarcely less celebrity than his contemporaries, Scopas [his teacher] and Praxiteles” (Harward 1932, 235n10). Some Roman sculptures thought to be copies of his work, most notably the Apollo Belvedere, have been distinguished with the highest reputation among classical works of art.

18. Attic figs were renowned; see Athenaeus, Deipnosophistae 14.67.

19. The word for “plant,” phuton, has the same root as the philosophically important word for “nature,” phusis. This is the last occurrence of any word related to phusis in the Letters.

20. Harward notes the suggestion of Ritter that “Leucadia” may rather have been the name of the ship (1932, 235n12).

21. A decent sum of money, roughly two and a half years’ worth of wages for a skilled laborer such as a carpenter (Engen 2004); see n. 143 to Letter Seven, noting that there were sixty minae to a talent.

22. It is not possible clearly to make out the event to which Plato is referring here. Evidently, some of Plato’s nieces died while he was in Syracuse. It is possible that Dionysius “provided Plato with a funeral banquet and pressed him, perhaps unceremoniously, to adhere to all the details of Athenian custom,” including the wearing of a wreath (Harward 1932, 235n13). But it is equally possible that Plato here refers to some occasion that merely coincided with, or bore some other relation to, the death of his nieces.

23. This sentence dates the letter fairly precisely. If this youngest of Plato’s grandnieces is less than one year old, but her mother’s death occurred while Plato was in Syracuse with Dionysius, then this must have been written considerably less than a year following Plato’s return to Athens.

24. The word for “must be given away in marriage” is ekdoteon, which in this context implies above all the need to provide a dowry. This word appears twice more in the next sentence, where the connection to Plato’s finances is made perfectly clear.

25. The third-person plural imperative form of the valediction I have translated “farewell” elsewhere in the Letters (chairontōn); cf. n. 1 to Letter Three.

26. On the value of a mina, see n. 21 above.

27. In Athens, wealthy residents were regularly called upon to pay for “liturgies” (litourgiai), i.e., to provide the funding for major public works. These included military expenditures, such as the outfitting of triremes, as well as cultural or artistic ones, such as paying for choruses to prepare and perform musical productions at dramatic festivals.

28. Apparently, Dionysius and Plato had hoped that someone wealthy, who shared ties of xenia with Dionysius and lived in or near Athens, might agree to loan funds to Plato, to be repaid by Dionysius, in case of urgent need.

29. On Erastus, see n. 1 to Letter Six. Andromedes is otherwise unknown.

30. Or “in a human way,” (anthrōpina), in the sense of “as any person would.”

31. The manuscripts here are corrupt, and it is impossible to know for certain what was written. “[H]ard to do business with” translates dussumbolon, which was the suggestion of Schneider and stands as the most likely guess. In any case, it should be noted that some word related to sumbolon, translated “token” elsewhere in this letter (see n. 2 above), appears here. Because the sumbolon was used between two contracting parties, the word could also refer to the contract itself, and hence dussumbolon means something like “hard-bargaining” or “hard to do business with.”

32. According to Plutarch (Dion 21), the matter at issue here is Dionysius’s desire to give Dion’s wife away in marriage to another man, his friend Timocrates.

33. Of Cratinus, nothing else is known. His brother Timotheus (fl. c. 375–360 BCE), however, was an eminent Athenian general, and a friend and pupil of Isocrates (see Antidosis 101–39, and the letter To Timotheus).

34. Both of the best manuscripts include notes in a second hand claiming that the correct reading is mala kalōn, “very beautiful” or “very noble,” rather than malakōn, “soft.”

35. The chiton was a typical ancient Greek tunic. The Greek version of the “cubit,” or length of a forearm, was the pēchus, measuring roughly 18 inches.

36. Cebes and Simmias were two Theban companions of Socrates, and his main interlocutors, in Plato’s Phaedo. See also Xenophon, Memorabilia 1.2.48, 3.11.17; and on Simmias, Plato, Phaedrus 242b.

37. See n. 2 above for a discussion of the important word sumbolon, translated “token” in this paragraph. In this context, it would not be out of place to use the translation “secret sign” or “password.” Bentley has provided what probably remains the most insightful suggestion concerning this cryptic passage: “The symbol [Plato] here speaks of made no part of the letters, nor began the first paragraph of them; for here’s neither θέος nor θέοι in that manner in any one of the thirteen. ’Twas extrinsic (if I mistake not) to the letter, and was a mark at the top of it in these words, σὺν θεῷ [“with a god”] if it was a serious one; otherwise, σὺν θεοῖς [“with gods”]. These two were the common forms in the beginning of writings or any discourse of importance: and in their usage were equivalent and indifferent; philosophers, as Xenophon and others, having it sometimes σὺν θεοῖς; and poets, as Euripides and Aristophanes, σὺν θεῷ. So that Plato could not have chosen a symbol fitter for his turn, being in neither way liable to any suspicion, nor any inference to be drawn from it to discover his real opinion” (1838, 412). It is unmistakable that Plato’s choice of password suggests some inclination toward monotheism; Bentley’s purpose in discussing it is to refute Cudworth’s argument that this marks Letter Thirteen as the work of a Christian forger. According to Harward’s note ad loc., this contention of Cudworth’s began the controversy surrounding the genuineness of the letter. On a close variant of the expression sun theōi in the Letters, see n. 20 to Letter Two.

38. There are no extant external sources that illuminate anything of significance about the details of these paragraphs. Nothing is known of these ambassadors or their mission, nor about either Philagrus or Philaedes, to whom Plato refers next, nor about Terillus or Tison, to whom he refers in the following paragraph.

39. The typical designation for the king of Persia, who would have been Artaxerxes II at this time.

40. Lit. “graceful” (charieis); on this usage, see Harward’s note ad loc.

41. The office of polianomos is known from inscriptions to have existed in a certain Tarentine colony in southern Italy; there was no such office at Athens. There is almost no evidence from which to deduce much about the rank or duties belonging to the title, but it seems it would have denoted a magistrate of considerable political status.

42. The word for “urge on” is protrepou, which means more literally “to turn someone or something toward some object or goal.” This same word is sometimes used in connection with exhortation toward philosophy, as it is thematically in Plato’s Cleitophon (see, e.g., 410e5–8).

43. “Fellow-spherists” translates susphairistas, a word that in some contexts would suggest “one who plays at ball with another” (LSJ, s.v.). This may be the meaning here, as is implied for example by Harward’s translation ad loc., “Give my greetings to your tennis-club” (see also Bury and Post, ad loc.). But Morrow prefers the other evident possibility, translating “Give my greetings to your fellow students of the spheres,” which, as he explains in a footnote, would refer to the study of astronomy (see also Post 1925, 140–41n16). One should not overlook the theme of Pythagoreanism in this letter, and in the Letters generally, in interpreting this strange phrase.

44. Nothing is known of this Aristocritus.

45. It is equally possible that this could mean “the men sent from me.”

46. Nothing is known of either Iatrocles or Myronides.