Just because it’s in a history book doesn’t mean it’s correct. In this detailed study of the Battle of Waterloo from 1815 (where Wellington soundly defeated Napoleon), someone has written tons of annotations (comments in the margins), correcting the author.
Given what he’s written, it sounds like the person writing the comments was right there on the battle field, and knows the subject better than the author.
If you have any ideas about how to figure out who this mysterious comment-writer is, let us know. If there are any juniors interested in European military history, the annotations in this book could lead to an excellent thesis topic!