I quote you Gibbon's summary of a part of his petition:

"The great and incomprehensible Secret of the Universe eludes the
enquiry of man. Where reason cannot instruct, custom may be
permitted to guide; and every nation seems to consult the
dictates of prudence by a faithful attachment to those rites and
opinions which have received the sanction of ages. If those ages
have been crowned with glory and prosperity--if the devout people
have frequently obtained the blessings which they have solicited
at the altars of the Gods--it must appear still more advisable to
persist in the same salutary practise and not to risk the unknown
perils that may attend any rash inovations. The test of antiquity
and success, (continues Gibbon), was applied with singular
advantage to the Religion of NUMA, and Rome herself, the
celestial genius that presided over the fates of the city, is
introduced by the orator to plead her own cause before the
tribunal of the emperors. 'Most excellent princes,' says the
venerable matron, 'fathers of your country! pity and respect my
age, which has hitherto flowed in an uninterrupted course of
piety. Since I do not repent, enjoy my domestic institutions.
This religion has reduced the world under my laws. These rites
have repelled Hannibal from the city, and the Gauls from the
Capitol. Were my grey hairs reserved for such intolerable
disgrace? I am ignorant of the new system I am required to
adopt; but I am well assured that the correction of old age is
always an ungrateful and ignominious office.'"

Symmachus was addressing a Christian emperor; and it was an ill
thing then, as in the days of Hadrian, to argue with the master
of the legions. Still, the method he chooses is interesting:
it holds a light up to the inwardness of the age, and shows
it dead. This was at twenty-one years after the death of the
Dragon-Apostate; whose appeal had all been to the realities and
the divinity of man and the living splendor of the Gods he knew and
loved. That splendor, said he, should burn away the detritus,
and make Romans men and free again. But Symmachus, for all his
admirable restraint, his rhetorical excellence, his good manners
and gentlemanly bearing,--which I am sure we should admire,--
appeals really only to the detritus; to nothing in the world
that could possibly help or save Rome. The Christians wanted to
be free of it, because they felt its weight; the Pagans wanted
to keep it, because they fo