Synesius of Cyrene (c.370-c.413) was a Neo-Platonic philosopher who became bishop of Ptolemais in the Cyrenaica. He left behind a small corpus of texts that offer much information about daily life in Late Antiquity, and about the christianization of the Roman world.
In his speech Dio, named after Dio of Prusa, Synesius presents his cultural ideal. Paideia or general education (which means: study of the arts) is a preliminary or an initiation to philosophy, comparable to the development of Dio, who was (according to Synesius) a sophist first, but later converted to philosophy (which means knowledge of the Divine).
The text is offered here in the translation by A. Fitzgerald. The green four-digit numbers are page numbers of the Migne edition.
Synesius, Dio 1
  Philostratus of Lemnos, in composing the Lives of the Sophists who had preceded him, divides them into two classes at the beginning of his treatise: first the sophists in the exact sense, and second those who, although really students of philosophy, had nevertheless been classified as sophist on account of their reputation for beauty of their language. He gives Dio his place amongst these, as also Carneades the Athenian, and Leo of Byzantium, and many others who passed their lives in the profession of philosophy, but had accustomed themselves to a sophistical form of style; and again he accounts amongst these Eudoxus of Cnidus, a man at first known as one of Aristotle's disciples, but also well versed in astronomy, at least as much of the art as was cultivated in those days.note[Synesius makes a similar remark about the early stages of astronomy in his treatise On an astrolabe.]
 For our part let Dio through all his works be a sophist, as he is said to be, in virtue of the range of that "tongue of gold" which he possessed, if anyone chooses to consider the cult of oratory an achievement proper to the sophist. The nature of this, indeed, we shall examine a little bit later.  If we consider his aims [however], Dio should neither be placed alone nor with the men just mentioned, but rather with Aristocles [of Pergamon] although he is to be contrasted even with him. Both of them changed their earlier attitude, but Aristocles was a man who from being a philosopher and an earnest one at that, and one whose brow was knit with thought, ended among the sophists, and not only indulged in every luxury, but even reached the culminating point.
 After spending the bloom of his youth in the advocacy of the Peripateticnote[Aristotelian.] views, and in publishing treatises for the Greeks with all the philosopher's enthusiasm, he fell a victim to sophistic opinion to such an extent that he repented him when an old man of the very seriousness of his youths, and in his contests shook the lecture-rooms of Italy and Asia with his declamations. Moreover, he had given himself over to the cottabus and introduced flute girls at dinner parties, and besides gave public banquets.
 Dio, however, from being a senseless sophist ended his life as a philosopher, and favored in this rather by fortune than by his own judgment,  has himself given us an account of that good fortune. So it was the duty of one writing his biography to describe the flaw in the man and not simply to reckon him thus with Carneades and Eudoxus. Whichever of their subjects you take, it is a philosophic one handled in a sophistical way; that is to say the style is wantonly, withal cunningly, set forth, and brings in much of the element of grace. In this way also by men whom they fascinated in speech by the beauty of their phrases, they were deemed worthy of the title of sophist, but it seems to me that they themselves would have repudiated this and would have declined it if offered, since philosophy brings such an expression into contempt, for Plato had just risen up against the name. But Dio showed forth brilliantly in each of these two walks of life respectively, and is at war with himself in his subjects, publishing speeches setting forth these opposite ways of life.
 Now we should not, methinks, pass over in silence the facts concerning this man, least of all on account of the discrepancy found in his speeches. As to what Philostratus says in the following passage, when he absolves him from blame for composing a panegyric on a bird called 'a parrot', on the ground that it is the part of a sophist not to scorn even such a subject, in all this he seems to confute himself, for he announced to us before that this man is one of the slandered, inasmuch as, though all the while a philosopher, he is dragged into being a sophist; for he speaks as follows:
 The ancients described as sophists not only those of their rhetoricians who made loud speeches and were brilliant men, but also those of the philosophers who expounded their thoughts in a fluent style. In behalf of these latter we ought to speak first, for although they were not sophists but only seemed so, they have passed under this designation.note[Philostratus, Lives of the Sophists 484-492.]
 Then he distinctly enumerates the men who are philosophers, amongst these Dio, and others after Dio, and in taking leave of the last of them, says: "So much for the philosophers who have the reputation of being sophists," only saying in another way the same thing, namely, that not being sophists, they usurped that name. And yet in the meantime he admits, it would seem, that he is in doubt in what rank of his chorus to place this man, for he is really very expert. What then did you say at first, and what afterwards? Was it that the one thing is, and the other only appears to be?
 For my part I do not split hairs over these contradictions, and I am willing to admit that Dio was really a philosopher and only played at sophistry, as long as he shall be found gentle and compassionate to philosophy, and has nowhere done her violence or marshaled against her reckless and evil-minded words. But this man of all the sophists had behaved with the greatest effrontery to philosophers and philosophy. The reason for this, I think, is that, since a nature full of power was allotted to him, even the practice of oratory made him speak the truth, for he was persuaded that it was better to live according to philosophy.
 It follows from this that his works directed against the philosophers are carried out with great attention to expression and shirk no brightness of language. The work addressed to Musoniusnote[A Roman philosopher, contemporary of Nero.] also was another of a similar language.  Dio was not merely exercising his powers in this instance, but was writing from conviction; I affirm this with every confidence and could easily convince another, given that he were clever at detecting truth and dissimulation of character in any sort of speech.