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 1.3
[1.3.1]  But just as of two roads the first cleft, diverging only a little, as it advances, ever adds something to the gap, so that finally the two come to be a vast distance apart; thus one may see in the case of the young, how a small tendency to differ separates them immensely as they advance in life. Now these lads turned in opposite directions, not little by little, but all at once, each receiving a separate lot, the one the perfection of good, the other the acme of evil.  As they grew up the antagonism of their choice grew with them; more manifest evidences of this were offered, stamped as they were on their deeds.
[1.3.2] Osirisnote[Aurelian.] from his earliest youth served as a general with those duly gazetted, although the law did not yet permit men so young to bear arms, but nevertheless he governed the judgment of his fellow generals, as though he were their intelligence, and made use of them as if they were merely his hands. Then, his nature growing like a plant, he brought forth fruit ever more perfect. He became commander of the guard, was entrusted with reports, was in charge of the audiences, president of the Council, and gave up each post in far greater repute than that in which he had received it.
[1.3.3] But the other,note[Typho.] when appointed minister of finance (for his father had thought best to make trial of his sons’ characters in lesser posts), brought shame upon himself and upon the man who had appointed him, for he was found guilty of embezzling public money, accepting bribes, and of instability in administration. When he was removed accordingly to another position of authority on the chance that he might be fit for it, he behaved still more disgracefully, and that part of the flourishing kingdom over which Typho was placed passed a whole year of unspeakable plight. He then betook himself to other men, and straightaway misfortune dogged him. Such was Typho as a leader of men. In private life, he danced the cordax,note[A dance from Greek comedy, associated with drunkenness.] and collected about him the most disorderly of Egyptians and strangers, those who were ready to say and to hear anything, to submit to and to do anything, so that his banqueting hall became a factory for every sort of licentiousness.
[1.3.4] Even when awake he snored, and was delighted when he heard others so doing, thinking this practice a wonderful sort of music; and there was praise and honor to that one who should prolong the unruly sound, and should spin it out most roundly. And a certain one of these men, the most heroic, was quite lost to shame, and shrinking from none of the infamies, gained many prizes, and certain posts in the government came to him as a reward for his disgraceful effrontery. Such an one was Typho at home.