A pagan imperial cult first appears in the archaeological record in 37 CE - Chrestianity.
Imperial chamberlains were seen to start the Great Fire of Rome in 64 CE as part of a property scam, in time to instigate the First, Jewish-Roman War.
The senior chamberlain in the Imperial court was Epaphroditus, a Chrestian, already known to us through the New Testament, as a colleague of Saul.
We have a contemporary account of Imperial chamberlains running with firebrands at the start of the Great Fire, which gives us some idea of their character - Epaphroditus, and his associates - Poppaea Sabina, Saul and Josephus included. They are not loyal to Nero, but to something else, Chrestianity.
Domitian executed Epaphroditus for the death of Nero and Domitian was then also killed by Chrestians.

“several ex-consuls did not venture to lay hands on his (Nero's) chamberlains although they caught them on their estates with tow and fire-brands... (Suetonius, The Life of Nero)”


There were no Christians during Nero Time, but instead, an imperial cult called Chrestianity; this became much like the Mafia and was responsible for starting Rome Fire, to aid in property speculation.
Chrestianity started as Greco-Roman, out of the resurrection of Cleopatra VII as Isis.


The archaeology of the Basilica of Saint Clement in Rome shows that it was built on the ashes of that fire.
https://en.m.wikipedia.org/wiki/San_Clemente_al_Laterano
https://www.nairaland.com/7393471/isis-chrest-chrest


A temple to Mithras in the home of the Clement family (Clemens), leading Chrestians of their day.

The researches of DeRossi, Le Blant, and others have made it certain that the monogram composed of X and P, which are the two initial letters of both XPISTOL and XPHSTOL(in Greek), preceded every purely crucial emblem.
This was the sign which, as is reported, Constantine adopted and placed on the imperial standard or labarum, by divine command at the time of his conversion to Christianity.
The so-called " monogram of Christ," however, is neither more nor less than the ordinary chresto. mathic mark of the ancients, standing which was customary to put on the margin ot manuscripts to indicate noteworthy passages, such passages, when put together in the form of a selection, being called a "chrestomathy."
That Constantine should have adopted, as the emblem of Christ, a sign which had long previously been in use to denote Chrest is full of significance. And that significance is enhanced by a fact which indicates the operation of those Egyptian influences that have been above alluded to-namely, that Constantine's conversion was in a great measure due to the representations of an Egyptian.
https://archive.org/details/chrestosareligi00mitcgoog/page/n36/mode/1up