good points — I think the disguise of the Principate continued until 3rd century when an Emperor divided the Empire 4 ways (what was his name, starting with D)
Diocletian. One of the very few absolute rulers in history who genuinely abdicated and went into retirement. And survived the experiment.
Although by his time the disguise had worn extremely thin. Diocletian simply brought the form of the state somewhat into line with its reality.
BTW, I thought it was odd the author of this essay drew a line between Greek/Roman and Persian attitudes towards the whole God-King bit.
Alexander had made himself a God-King while he was still alive and his diadochi followed suit enthusiastically. The Ptolemies and Seleucids were Gods.
Even the earliest Roman emperors were worshiped as Gods outside Italy while they were alive, and all but the most unpopular were deified and worshipped after death in Rome itself. There is a great story about Vespasian, one of the more attractive of the early emperors, renowned for an iconoclastic sense of humor. His last words reportedly were, “I feel myself becoming a god.”
The later Emperors, of course, were God-Kings from their accession.