The Augustus of Prima Porta, photograph by Justin Benttinen in Wikipedia “Augustus” under license https://creativecommons.org/licenses/by-sa/4.0/deed.en
(4) IMPERIAL CULT
For the God-Emperor of Mankind!
I mean, what better for an empire than literally deifying it, or at least the emperor, in an imperial cult?
“The imperial cult of ancient Rome identified emperors and some members of their families with the divinely sanctioned authority (authoritas) of the Roman Empire.”
The most famous imperial cult is indeed that of the Roman Empire. The Roman imperial cult was somewhat more nuanced than declaring a god-emperor and has sufficient features for its own top ten, but was intertwined with Roman state religion and traditional deities.
However, the Roman imperial cult offers a useful distinction between an imperial cult and my category of ideological empire where the latter’s “ideology” is a proselytizing religion. Typically, religious ideological empires do not involve an imperial cult as such, although they may identify their rulers as divinely anointed or otherwise with some divine right or agency within their religion.
Prior to adopting Christianity as its state religion and hence transforming its imperial cult beyond recognition, the Roman Empire was incredibly tolerant or syncretic when it came to the religions of its imperial conquests and subjects, although there were exceptions. While it did often seek some formal obeisance to its imperial cult, It did not seek to convert its conquests or subjects to that cult or its own religion – indeed, more often than not, it imported other religions. This was often in the form of syncretism identifying its own deities with those of their neighbors or subjects, most famously combining Roman deities with Greek ones.
The Roman imperial cult is but one of many historical imperial cults, which in turn followed on from divine kings or monarchies – Egyptian pharaohs, the imperial cult of Alexander the Great, Chinese emperors, and so on. A few surprisingly persisted even to modern history, such as that of Japan, but imperial cults were mostly transformed by religions such as Christianity into concepts like divine right – and by modern political ideologies or charismatic politics into cults of personality.
Of course, the most fun imperial cults or the use of God-Emperor as a term remains in science fiction, notably the God-Emperor of Frank Herbert’s Dune series and the God-Emperor of Mankind in Warhammer 40K.