In his speech On Imperial Rule (or On Monarchy), Synesius of Cyrene offers some advise to the emperor Arcadius (r.395-408). More information about this speech, together with a brief summary, can be found here.
Throughout this speech, the word "Scythians" refers to the Tervingian Germans (who would later be known as Visigoths), whereas "king" refers to emperor.
The text is offered here in the translation by A. Fitzgerald. The four-digit numbers are page numbers of the Migne edition.
On Imperial Rule 11
  Now although nature promises us strength of soul, it is training which perfects it. To this, my liege, philosophy exhorts you, she who is ever on her guard against those consequences which arise from speech; for everything is destroyed by forces which are the contraries of those which sustain it. And I do not think that the ancient institutions of the Romans should be transgressed by the king.
 Consider as ancestral traditions of the Romans not the things which yesterday  or the day before came into the commonwealth when it was already changed in its habits, but those by which they won their empire. Come then, in the name of the God who presides over kingship (and you must try to bear with me, for my story bites into the soul) at what period do you esteem the affairs of the Romans to have been in the most flourishing condition? Is it from the time in which you have been robed with purple, and bedecked with gold, when you wear gems from foreign mountains and seas, placing them, now on your brow, now on your feet, now round your waist, now suspended from your person, now buckled on your garments, now used as a seat? You have certainly in that way been made a variegated and multicolored vision like the peacocks, drawing upon yourself the curse of Homer, the 'tunic of stone'.note[Homer, Iliad 3.57.]
 But not even does this dress suffice you, for you cannot go into the council-chamber of your peers when you have to exercise the rule belonging to your title, either when they are electing magistrates, or when they are seated in counsel for the consideration of any other matter, unless you have wrapped yourself up in such and such a robe. And now you are looked upon by men who may lawfully behold you, and they alone are happy among the senators, as alone of the senators bearing the burden of government.
 Nay, you even exult in your burden just like one chained with gold or rather bound by fetters worth many talents, but should not feel the evil at all, nor think that he was enduring terrible things ending in incarceration, for he would be deceived by the very magnificence of his misfortune. But no more will he have liberty to stir than those who are bound in the 'foot-plague', the meanest of stocks. Again, for you the pavement is insupportable, nor may you walk about on earth in its natural state, but gold-dust must be sprinkled upon it, which your wagons and merchantmen bring you from far-away continents. And you have a host not to be despised who besprinkle the mound; or you deem it not kingly, unless you exhibit luxury even in the straps of your sandals.
 Do you now fare better since the time when this initiation, usual with emperors, was instituted, and since you have taken to keeping your lairs like lizards, scarcely peeping out at all to enjoy the sun's warmth, lest being men you should be detected as such by men? Or was it then when men living in the throng, blackened by the sun, led armies to battle, and bearing themselves in all other respects simply and artlessly, instead of in a manner suggestive of the dithyramb and the tragic stage, in Lacedaemonian caps, which when seen in statues arouse the laughter of striplings, and not even the old folk think that such kings are fortunate,  but in comparison with you, unfortunate in the extreme?
 Now it was not by walling off their own house that they prevented the barbarians either of Asia or of Europe from entering in. Rather by their own acts did they admonish these men to wall off their own by crossing the Euphrates repeatedly in pursuit of the Parthians, and the Danube in pursuit of the Getae and the Massagetae. But now do these nations spread terror amongst you, crossing over in their turn,note[A reference to the Battle of Adrianopel in 378 CE.] assuming other names, and some of them falsifying by art even their countenances, so that another race new and foreign may appear to have sprung from the soil, and they dare to demand an indemnity as the price of peace, 'unless thou arm thyself with valor'.note[Homer, Iliad 9.231.]
 But let all comparisons of the past with the present be dismissed, if you please, that we may not seem to censure you in the guise of good counsel, by showing you that just to the extent that a monarch's regime inclines him to pompous display, to that extent it is deprived of reality.