Wax seals were used as a form of identification as well as a way of closing or sealing a document.
The seal identified who the document was from and, if it arrived intact, the recipient could tell that it had not been opened.
Pictures on seals were usually a representation of the person they belonged to, with a motto around the edge.
A Great Seal was one that belonged to the king or queen. All documents relating to the monarch had the Great Seal upon them, and it was a way of knowing that the document contained the wishes and commands of the king or queen - the royal 'seal of approval'. The more important you were the larger the seal.
Look closely at the seal and discuss what you see. Note that the queen is dressed very grandly and holding the orb and sceptre - symbols of power. Also note the symbols for England (lion), Ireland (harp), Wales (dragon), France (fleur-de-lys) and the Tudor rose.