I can’t do better today than to urge you to read this great blog post by Dr Eleanor Janega of the London School of Economics, which explains everything:

Knights killing Jews at the time of the First Crusade (1000s AD)
I can’t do better today than to urge you to read this great blog post by Dr Eleanor Janega of the London School of Economics, which explains everything:
Knights killing Jews at the time of the First Crusade (1000s AD)