Answer: The majority, if not all, of printed documents were "stamped" as a result of the Stamp Act of 1765.
Step-by-step explanation:
The Stamp Act was imposed by Great Britain onto the American colonies, taxing everything from almanacs, pamphlets, legal documents, and even mediums like the newspaper.
While previously speculated that this "proof of payment" was these new Americans fulfilling their share of tax payment, they were actually used to fund ever growing militia of Great Britain; causing an eventual outrage.