Although The Egyptian Tale looks like a retelling of a part of the myth of Isis and Osiris, it is obvious that the two brothers Osiris and Typho represent good and bad government. The story, however, is not just a myth, because the man called Osiris can be identified as Aurelian, praetorian prefect of the Eastern Empire during the reign of Arcadius (r.395-408), and one of Synesius' benefactors. The other people in this ancient roman à clef, however, are less easy to identify, but an attempt is made here.
Synesius, On Providence 1.8
[1.8.1]  Now as soon as he was initiated in the kingly office by the gods and his father, they definitely announced to him, from definite knowledge, besides all the rest, benefits in swarms, but that his brother who had been born to bring ill-luck both upon the Egyptians and on his father’s hearth, must be banished if he were not to throw all things into confusion, to the end that he might neither hear of nor see the success and prosperity of Egypt that were due to the reign of Osiris himself.note[Aurelian.] For Typho’snote[Unidentified.] nature could endure nothing good.
[1.8.2] The priests now transmitted to him Osiris knowledge of the double essence of souls as well as the necessary opposition between those on the earth and those above. These then they begged him to remove and to strip the evil element from its good and divine parallelism, and to be in no wise ashamed before what is called by men blood relationship. And when he showed weakness, they told him that he, and the Egyptians, and their neighbors, and all the country ruled over by the Egyptians must suffer; for that the evil in question was no slight one,  nor would any ordinary care be an adequate means of rebutting and weakening upon and secret attacks. The reason was that Typho had allies with him also, a powerful company of those malignant demons to whom he was next of kin, and by whom he had been brought into existence in order that they might be able to make use of an implement of their evil towards men. It was for the sake of this evil, that as they advanced on their way, they engendered, nourished, delivered his mother of, and brought up after their own fashion to be a great boon to themselves – Typho! One more thing they thought necessary for complete possession, namely to endow him with the power that rule brings with it, for then he would be a perfect man of perfect ancestors, in that he would be both able and willing to do great evils. ‘You, on the other hand,’ said one of the priests, ‘they detest as being a blessing to men and retribution to themselves; for the misfortunes of races of men are a feast to the evil demons.’
[1.8.3] Again then and very often the priests gave him this warning advice, namely to conduct his brother beyond the frontiers, and to let him go to some distant place, for they knew and saw the gentle character of Osiris; but they were finally compelled by him to tell him that for a time he might hold his ground, but that unknowingly he would surrender and utterly betray himself and all men, exchanging in reality the greatest disasters for the benign brotherly affection. ‘Nay, as long as you at all events are propitious and helpful,’ replied Osiris, ‘I shall not fear my brother remaining, and I shall be exempt from wrath of the demons, inasmuch as it is easy for you, if you are willing, wholly to remedy oversight on my part.’