Why? Because I'm going to be writing about war. But you're writing about knights. Yes, but there are things that never change about war. Photos of guns and helicopters are all well and good, but the ones that I pull for reference are more about the experience. I'm never going to fully understand what soldiers go through, but I'll take what points of reference I can find.
And this one is just cool:
Where do you find reference photos for abstract things like war?