Pioneered by eighth-century Chinese, developed by twelfth-century Arabs, used extensively by fifteenth-century German and Italian printers, paper, a substitute for parchment, made printing on a mass-scale possible. Like their fellow artisans, paper makers longed to put their mark on their product. Quite by accident they found a way to do this. In the paper-making process, pulp sifts over a wire screen. Somehow a bend piece of wire fell on one of these screens, and as the pulp was pressed against the screen to remove excess water, the imprint, an imperfection in texture was made. Today watermarks add prestige to some papers, particularly the better-quality rag-content bonds.
The love of medieval rulers for pomp and pageantry ushered in an era of heraldry. Artists of the Dark Ages kept themselves busy designing coasts of arms and crests. We find in heraldry an unlimited sphere of expression throughout an epoch of more that 1,000 years.
Heraldry flourished in the twelfth century to help warriors distinguish between friend and foe. Because suits of armor all look very much the same, battle leaders designed the crests to identify to identify their own soldiers.
The marks appealed to civilians too, and "Coats of Arms" became popular with all aristocrats. Today the College of Arms, London, decides which English families are entitled to display coats of arms, but no such agency attempts to police heraldry addicts in America.
Trademarks have some relationship to cattle brands, which date from the medieval custom of putting family marks on everything a family owned. The early-arriving Spaniards first branded cattle on this continent.
Hobo Marks: Over the years hoboes develped a special sign-on-fense language as an aid to their fellow travelers. A drawing of a cat, for instance, meant that a "kind lady lives here." A cross meant that "religious talk" gets a free meals.