“The watermark, a translucent emblem produced by pressure from a raised design on the mold and visible when the sheet of paper is held to the light, was used in Italy by 1282. The origin of this design device is unknown. Trademarks for paper mills, individual craftsmen, and perhaps religious symbolism were early uses. As successful marks were imitated, they began to be used as a designation for sheet and mold sizes and paper grade. Mermaids, unicorns, animals, flowers, and heraldic shields were frequent design motifs.”

—Phil Meggs & Alston Purvis, Meggs’ History of Graphic Design, 2006.