Plate
was marked at Edinburgh from 1457 onwards. Date letters started in 1681.
Prior to this date, a "Deacons mark" was stamped on the piece, to be replaced
by the Assay Masters mark. This practice continued until 1759 when it was
replaced by a Thistle mark. The Thistle mark continued until 1975 when
it was replaced by a Lion Rampant. The date letter, which followed a 25
year cycle, was changed in October until the Hallmarking Act of 1975 when
it (along with all other remaining British date letter sequences) changed
in January.
