Heavy on the purple prose and hyperbole, but light on the details. The details thing is to be expected in book covering a thousand years or so. The love-letter to Richard I of England was pretty spectacular, though. You could do worse for Baby's First Crusade Overview.

Zero excuses for the lack of referencing, though, even on directly quoted material. Be an academic textbook, or be a short introduction. Don't try and fail at both.