Let me try saying this another way... 2015 years of stuff happening. Not just Islam. Lets stop trying to nitpick.. Evil is evil and evil is going to continue to happen until Jesus does return. Who knows when that'll be.
That doesn't include war with the Barbary States (radical Muslims) which forced even our earlier presidents to see it as a threat. Ottoman rule was generally brutal up until the fall of the Empire in the aftermath of WWI.
Islam is generally a war-making religion. Born in war. Expanded by war. Perpetuated by war-like actions. While its most radical forms are not a threat for 100% of history after Christ, Nazism is an aberration by comparison.
Or allow me to explain it this way, if you are any sort of Westerner, Islam, left unchecked by strength of arms and principle, will seek to dominate you. It may lie dormant...but it's still there.