OP: What you are overlooking is that the fall of the Roman Empire was not due to widepsread immorality as many believe, but in fact the collapse only began when Chrisitanity replaced Polythesism under Constantine I; for 750 years the Romans built a civilisation unmatched even by today's standards and then in only 175 years the Christians completely destroyed it.

And, before you start to proclaim Theodosius I as some ersatz Holy man, you'd better know that he was excommunicated in 390 by Ambrose Bishop of Milan. True: he did ban all pagan worship -in public or private- and closed all their temples, but after diminishing them in a 4-year war, he also allowed the Visigoths to settle onto Roman territory which only allowed them to return to attack years later and destroy what little he had accomplished. When Theodosius I died in 395, he left what remained of the eastern Empire to his 17yr old son Arcadius and the western portion to his 10-yr old son Honorius. They were both feckless rulers who in turn passed Rome on to their own young wildly incompetent sons. They also chose not to engage those same Visigoths their Daddy had stupidly not banished and in 410 the Visgoths sacked Rome itself.

Many people are under the impression that Constantine was a noble Emperor dedicated to Christianity. The Church itself promotes this endlessly, but it is utter bullshit! In reality, he saw in the Christians an easily-led power bloc that would help him seize control of the Empire and once he attained the throne of Rome he only tossed them crumbs in return. He raised taxes to inordinant levels, prompting the Christians to rebel - they thought that since they shared the same beliefs as the Emperor they should get special treatment and demanded same! Instead, Constantine spent those taxes on bejewelled robes/slippers and built a new, massive and lavish capitol city -Constantinople- which he vainly named after himself. Should I also mention that he murdered his own wife and son?

Further -in spite of his public worship of Christianity- Constantine refused to be baptized into that faith until he was virtually on his deathbed and even then only wanted to have it done in the Jordan River as a PR stunt; he never made it and was killed enroute at the hands of a disgruntled Christian; this occurred shortly after his baptism by devoted acolyte/ass-sniffer Eusebius - who was a wealthy Priest, self-proclaimed religious historian and propagandist... he was nothing more a shameless brown-noser whose sole purpose was to establish himself as the only authority on the Catholic Church. It was Eusebius who wrote all the texts that proclaimed Constantine a legendary Christian ruler when in fact they were both nothing more than a couple of con artists! Eusebius was likewise instrumental in assembling those Biblical scriptures at the Council of Rome, even though he too had been previously excommunicated for heretical beliefs... but to this day, the Catholic Church holds him aloft in near-Sainthood!

There were 25 Emperors after Constantine and all but one of them were "Christians" - the sole holdout was Julian who was immediately branded an Apostate when he attempted to return Rome to it's earlier religious practices. Julian was a very popular ruler because the average Roman citizen was already weary of the constantly restrictive Christian tenets and because Julian lowered those high taxes that Constantine and his immediate followers had levied. The other 24 Christian Emperors ran Rome right into the ground and that's what caused the Dark Ages where your preciously omnipotent Church banned all formal study outside of itself and in so doing marched civilisation back a couple of hundred years in the process.

One final thought: your greatest mistake is in believing that the Catholic Church is infallible when history has proven endlessly the exact opposite. This renders your final sentence above the most ludicrous of all: that a Church is authoritative and infallible just because it claims to be and that this magically somehow makes it true. And for you to further suggest if you do not accept that declaration as fact then you must then dismiss the entire New Testament only adds insult to your thoughtless philosophical injury.

You Sir, are a fool of the greatest magnitude who clearly knows very little of the documented, ancient history that your Church has ardently supressed for 1500 years.