Stamped paper is an often-foolscap piece of paper which bears an imprinted revenue stamp. Stamped papers are not a form of postal stationery as although they may contain writing, they are not designed to be used to convey a message.
The use of stamped paper in the American colonies was so unpopular that it has been credited with sowing the seeds of the American Revolution.
The Stamp Act 1765, also known as the Duties in American Colonies Act 1765 (5 Geo. 3. c. 12), was an act of the Parliament of Great Britain which imposed a direct tax on the British colonies in America and required that many printed materials in the colonies be produced on stamped paper from London which included an embossed revenue stamp. Printed materials included legal documents, magazines, playing cards, newspapers, and many other types of paper used throughout the colonies, and it had to be paid in British currency, not in colonial paper money.
The purpose of the tax was to pay for British military troops stationed in the American colonies after the French and Indian War, but the colonists had never feared a French invasion to begin with, and they contended that they had already paid their share of the war expenses. Colonists suggested that it was actually a matter of British patronage to surplus British officers and career soldiers who should be paid by London.