He is refering for Post Marian Romani army of having A LOT of 1st Cohorts. (legionaries with the eagle on top them) That thing raises the moral of troops around.
Its a little of an exploit as the legions usually had 1 unit of those, and having most of your legions being those guys makes your army extremely hard to rout and very-unhistorical.
thats all really, its not a "huge" deal.
Bookmarks