Archimedes, if memory serves, discovered calculus 1400 years before Newton but his work was lost in the Dark Ages.
Not so much lost as scraped away and overwritten by the Church.
I was lucky enough to have seen the Palimpsest when it was on display at the Walter's (one of my regular haunts from the time I was 6 or so) back in 1999 IIRC.
2. Pagan cultures didn't invent and produce the cans and can openers.
Pagans invented coinage, writing, mining, the iron age, the bronze age, boats, mapping, discovered the diameter of the earth, mapped the heavens, invented clothing, domesticated animals, wheat and bread, fermenting, developed corn...