Christian civilizations became the most advanced civilizations on the planet.
beacuse they were very good at murdering scores of other civilizations that were of other religions, "converted" such heathens, and were smart enough to not outright torch all of these civilizations' more practical, and useful advancements.
Sure, a lot of knowledge was burned and obliterated under the guise of blasphemy (as with any conquering nation running under the banner of X god), but at the very least, the conquering Christian nations were advanced enough, at the time, to realize that jettisoning all technological progress and knowledge was a bad idea.
Sure, guys like Gallileo are famous examples of retardation winning over progress, and certainly stagnating a few centuries'-worth of growth, but the Christian nations still maintain a "decent" record of allowing for growth in knowledge.
And don't forget that the Islamic nation at the time of Sala'hadin was probably the most advanced in the world, and did as much for technological advancement and culture as any nation-under-religion has ever done. Simply because these guys ended up losing some rather important battles, at one particular time, doesn't discount such contributions, and what could have been.
basically, simply saying that "Christian civilizations became the most advanced" and leaving at that, is dubious and uninformed at best, spurious at worst.