Kinda ironic that you put it in those terms, when it was cristianity itself during the dark ages that almost destroyed the individuality for much easier control of the masses. The crusades, the inquisition, the witch trials, hundreds of thousands killed in the name of trying to annul everything that was different and that didn't mold itself by the christian thought and moral code.
It's disingenuous to say that Western Europe had a big fall because of the rise of Christianity, even though the Dark Ages coincided with it. The Church was pretty much the only vehicle keeping knowledge alive in the West (which gave them a monopoly on information that they later abused to an extent), so they deserve credit, as if the Church hadn't been around as an institution, most of that knowledge would have been lost (though it would have been reclaimed i suppose)
Plus the Church ended a few barbaric practices of pagan times. I'm not saying the Church is blameless in history, far from it, but it isn't responsible for the dark ages
Monster Hunter: pissing me off since 2010.