The copies of books that survive in our libraries show passages underlined, and agreement or disagreement signified in marginal comments: one reader of The Compleat Horseman and Expert Farrier (1639) by Thomas de Gray, esquire, so strongly disapproved of its advice that he crossed out “esquire”, and deleted the prefix “ex” in the book’s title to make it read The Compleat Horseman and Pert Farrier. “Oh the cretin”, he wrote in the margin.
Joan Thirsk, Horses in Early Modern England, For Service, For Pleasure, For Power (1978)