An item that Anthony Alcock translated some time ago, but did not reach me, is three texts by the 5th century Coptic abbot Shenoute, which are concerned with invasions by “Ethiopians” – presumably Nubians – at that period.
It will be remembered that the temples at Philae, on the southern Egyptian border, remained open for the use of pagans across the frontier, even after all the pagan temples had otherwise been closed. Doubtless this was just a security matter; but it must have been a rather odd situation. How, in an empire in which paganism was illegal, did the temples recruit priests?
But then again the Roman empire was not a modern state with the ability to impose totalitarian control on its people, and no doubt the answer was that matters continued for the most part as they had always done, and the temples were mainly staffed by locals.
Here is Shenoute’s short works on the aftermath of these invasions.
I remember reading that the priests of the temple of Philae all belonged to one family. For several generations the priesthood would simply go from father to son.
That would explain it.