Definizione

• Seal.  A metallic bas-relief object, much like a medal, the possession and use of which indicates authority. To provide this authentication the engraved relief seal is used to
  make a wax impression (later impressed on paper) attached to some letter, contract or document. This may have been in imitation of the Oriental custom of stamping (with ink) a document with a personal seal, often a name only in Oriental letters. This practice still continues. (The use of the notary seal performs this practice today.)
  While the seal was in relief, the wax impression would be negative, leading to the use of a negative seal (called the matrix seal) to impress positive wax seals. More important papers or documents were impressed with a seal in metal, called a bulla (particularly in warm climates where wax would be impermanent). The bulla was often attached by a cord to the document, and infrequently, on treaties, or on select important documents, the seal would be impressed in molten precious metal. The impression, wax or metal, could be housed in a metal case called a skippet.
  Thus seals can be many things: the metal object (often with a handle) for stamping (the matrix seal), the carved or engraved metal seal alone (similar to a medal mounted in a press), the wax or metal impression from any of these, or, ultimately, the illustration of the impressed design. Transporting the official seal of some great authority was an important activity of some functionary. This evolved to something the authority himself could carry and the development of the signet medal, or the more popular signet ring. This could be impressed into wax or soft metal on documents signed away from home or headquarters.
  The designs for seals evolved from simple devices to elaborate creations. These included coats of arms, royal trappings, crowns and symbols to royalty on horseback, seated on a throne, holding a mace or similar scenes. Large round seals for heads of state were called the great seal. Other seals were smaller, and some were not round. Like medals and charms, seals for religious organizations were almond shaped or pointed ovals (mandorla or vesica piscis (with pointed ends at both top and bottom).
  The engravers of seals were the same engravers of coins and medals (who better to be sealmakers?). Often the most famous coin or medal engraver also prepared seals. Benvenuto Cellini was one of these, so was Benedetto Pistrucci, Thomas Simon, the Wyons, most every well-known engraver created seals. It is rare to find a seal engraver (seal cutter) who did seals only.
  With further evolution seals became trademarks or logos and every institution in the modern world has such a device today. More likely, however, the seal is of two dimensions – for illustration – rather than three dimensions for sealing a document.
  Cylinder seals.  A special seal was in the shape of a cylinder. It could be rolled
  across a flat surface and provide a long strip of impressed design. As old as flat seals, cylinder seals required the engraving on a curved matrix. An exhibit of cylinder seals is usually shown with a rolled out impression of their full surface. Engravers early learned it was just as easy to carve a design on the curved surface as a flat surface.
  Seals in numismatics.  Because they are so much like coins and medals, relief seals are considered numismatic. The Royal Mint, London, has made seals for colonial governments, for many public offices and for numerous British institutions. In the United States much of the design for government seals is performed by the Institute of Heraldry.
  Seals and seal impressions are cataloged in much the same manner as coins and medals. The same terminology is used in their description for the most part. They have borders, devices, inscriptions, fields, signatures, portraits. Perhaps the only thing they do not have is edge marking (since only one or two sides can be impressed). When an impressed seal has two sides, they are not called obverse and reverse, but obverse and counter-seal (the back of a seal is made with a counter-die).
  Seals lack, greatly, the popularity of coins and medals among collectors, but seals do have an extensive literature. Librarians identify all the above as "seals (numismatic)" as in a library catalog, to differentiate from other seals (particularly the marine animal, container closing device or the institutional logo).
  References:                                                                                                                                  
  S5    {1974} Stafford and Ware, p 194.
  X10 {1976} Patterson and Dougall.
  X11 {1987} Friedenberg.
                          Seal Terms                      
                                                          
      Counter-die.  A back die as when embossed; it may or 
      may not bear a design different from the obverse die.
                                                           
      Great seal.  The seal for a nation.                  
                                                           
      Matrix die.  A back die; the same as a matrix or male
      die; it bears the same design (in mirror image) as   
      the obverse die. A diesinker could make a matrix die 
      by hubbing.                                          
                                                           
      Pendant seal.  Not affixed to the surface of the     
      document, but a separate seal attached by a cord.    
                                                           
      Seal paper.  A separate adhesive paper, circular or  
      scalloped shaped and slightly larger than the seal,  
      which receives the impression of the seal die.       
                                                           
      Seal wafer.  A modern type of seal paper, red in     
      color, which receives the impression of the seal die.
                                                            
      Skippet.  A circular case or box which protects      
      the seal impression; a cord passes through all the   
      pages of the document, the seal and the skippet.     
                                                            
      Skippet cover.  A top metal lid to the case which    
      is often engraved with the design of the seal found  
      inside.                                              
                                                           
      Siligraphy.  The scientific study of seals.          

  excerpted with permission from

  An Encyclopedia of Coin and Medal Technology

  For Artists, Makers, Collectors and Curators

  COMPILED AND WRITTEN BY D. WAYNE JOHNSON

  Roger W. Burdette, Editor

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