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Did Ololo kill a horse with plates while a knight was riding across the field?

Knights only put armor on their horses during battle; otherwise, what's the point if they won't even reach the battlefield by the next century? A proper elf will shoot the horse down then. At worst, a knight without a squire isn't very effective – he can't armor the horse himself, nor can he armor himself. And squires weren't wealthy enough to wear proper armor.