What you have here is a mixture of history (mostly written by the Roman victors) and belief; which is personal and subjective. Terry Jones' Barbarians is an excellent rebuttal of Roman propaganda made history. They considered our Celtic ancestors to be barbarians when it was the Celts who had a high civilization with social policies (Brehon Laws) which would not be replicated until the 20th century.
The stories of Celtic gods are considered legends because few if any people believe they are divine. To me the stories of Judeo Christian, Roman, Greek and Pheonician gods are no different.
Josephus hated the romans and he wrote extentensively, so its not all ancient roman view point,
also Caligula wasn't called Caligula that was his nickname (little boots) apparently he hated that name which his mother called him as a kid.
So Roman culture even hated their own big bosses
And the roman army were right into the mystery cults
bit like our army
Also the ancient saints writings are still available which were being burned and tortured by the Roman Empire and its Stalin type state
Terry Jones is a comedian and he takes history anomalies and tries to see the fun in them
he also enjoys playing the piano naked in front of audience, so I would suggest he has an interesting take and opinion
I like Terry jones btw
so ill try get copy of that book
but try the church fathers and the famous doctors of the church and see if you still feel that the history they kept is trustworthy
its a bit like saying Irish culture has being tormented by British historians
and it has but sometimes you get hold of books that ring true even in a world of propaganda
compare the modern mystery cults with the gnostic writings captured by saint ireneus in his masterpiece against heresies, written in gaul, Lyon circa 150
try the epistles of Ignatius of Antioch circa 100 ad
try Josephus
try Justin martyr
try the writings of Athanasius of Alexandria
or Augustine of hippo (voluminous masterpieces including his confessions (ex manichean)
try origen
try Ambrose of milan
Try Thomas aquinas
or Albert the great
or Boneventure
or Anselm
or isador of seville
try the ancient Irish saints writings
none of these blokes were influenced by roman empire
or if they were they tell a story that rings true
more true than the life of Brian comedians who pick snippets and make laughs
the list of ancient writings are uncountable to chose from
the above list is just some of the good ones
Another cracker is St John damascene who was bishop in syria and his chats with the early muslims who couldn't answer his apologia
Romans got smashed by Alaric the goth and Attila the hun
perhaps its really Hunnish version of roman world that jones is interested
the persecuted bishops, most of which had being tortured by Rome
some blind some with limbs amputated met at Ephesus for massive council
that council is freely readable and none of them hated the romans
in fact the emperor was there to witness it
Im not saying buy anything I say
but im suggesting that roman culture although influential was not deterministic in the destruction of all truth