Dating english silver plate
Series of alphabetical letters were chosen to indicate the year of assaying (date letter) using "cycles of letters" of different font and size inside punches of various shapes.
Any Assay Office adopted its own cycle of date letters so that only from the 1975 the four surviving Assay Offices use a uniform system of dating (optional from 1999).
It was not until 1856 that the leopard's head mark could have been used for any purpose other than a fineness mark.
Birmingham has the anchor, Chester the three wheat-sheaves and sword, Sheffield the crown and the Tudor rose (from 1975).
In clause VIII of the Act 8 & 9 William III c.8 which, among other things, deals with the marks that must be applied to assayed plate at Goldsmiths' Hall the following wording is used: " ....
The work they part or wholly produced was marked under somebody else's name.In 1867 the Foreign Mark was introduced adding an "F" to the appropriate British hallmark.