The “Great Seal” signifies that a document carries the force of the will of the Monarch and, interestingly, on December 11th 1688, while attempting to flee to France, James II threw his Great Seal into the River Thames, hoping that the machinery of government would stop. It didn’t. His successors, William III and Mary II just had a new one made!
Since 1066 we have had the Great Seal, which is kept by the Lord High Chancellor, obviously it is not with the same one! Sovereigns designed their own, but not only monarchs, after the civil war Oliver Cromwell had a special seal made inscribed “The Great Seal of England, 1648” to prove his power.
Some monarchs had several, Queen Victoria had four different ones during her 63-year reign, while today’s one was struck in July 2001 replacing the 1953 one.
Isn’t history Fun!