Greek Fire...

[a completely inoffensive name]

Religion did not destroy the knowledge and technology, the massive influx of "barbarian" tribes into the Roman Empire that toppled it, did.

EDIT: To clarify, I am not saying the invading tribes themselves destroyed it, I am saying the fact that the Roman people didn't pass on their knowledge to the invading tribes did. I would enjoy an explanation from someone as to why all this great knowledge never passed on to the invaders, I would think it would be held as very valuable to a warlord looking to expand his tribes empire.