Seals are known since more than 5000 years as distinctive marks,
attestations or to close letters and documents.
Seals are made by engraved sealing stamps (metal or stone),
pressed on wax, lacquer, clay or (soft-) metals like tin, lead, silver or gold.
Different themes of seals are existing, for example: emblem seals, town seals, monogram seals, portrait seals, craft seals...