TL;DR The London assay office mark is a leopard's head, struck at Goldsmiths' Hall. It was crowned until 1821 and uncrowned since, which dates a piece at a glance. London date letters began in 1478, run in 20-letter cycles, and changed each May until 1975, when all UK offices adopted one letter changing on 1 January.
The leopard's head is the London assay office mark, and the oldest town mark in British hallmarking. A statute of Edward I in 1300 required silver to meet the sterling standard and to carry a leopard's head. The Goldsmiths' Company has run the London office from Goldsmiths' Hall since 1478, the year the date letter appears.
What does the London leopard's head mark look like?
The London mark is a lion's face seen from the front, called a leopard's head in heraldry. Before 1821 it wears a crown; from 1821 it is uncrowned. That single detail splits London silver into two eras before you read anything else, and the outline of the head and its shield changed at intervals that a date table records.
Between 27 March 1697 and 1 June 1720 London sterling was replaced by the higher Britannia standard, 95.8% silver. In those years the leopard's head gives way to a lion's head erased, and a figure of Britannia replaces the lion passant. Britannia silver stayed legal afterwards as an optional higher standard.
How do London date letters work?
London date letters run in cycles of 20 letters, A to U with J left out, and each cycle changes the letter style and shield shape. Until 1975 the letter changed in late May, so a London letter covers parts of two calendar years. Since 1975 London shares one UK letter that changes on 1 January.
| Cycle | Years |
|---|---|
| Cycle beginning with the Britannia standard, March 1697 | 1697 to 1715 |
| 1716 cycle (omits J and U, ends at V) | 1716 to 1735 |
| 1736 cycle | 1736 to 1755 |
| 1756 cycle | 1756 to 1775 |
| 1776 cycle | 1776 to 1795 |
| 1796 cycle | 1796 to 1815 |
| 1816 cycle | 1816 to 1835 |
| 1836 cycle | 1836 to 1855 |
| 1856 cycle | 1856 to 1875 |
| 1876 cycle | 1876 to 1895 |
| 1896 cycle | 1896 to 1915 |
| 1916 cycle | 1916 to 1935 |
| 1936 cycle | 1936 to 1955 |
| 1956 cycle (cut short) | 1956 to 1974 |
| Shared UK cycle | 1975 onward |
Read the style of the letter as closely as the letter itself: case, typeface and shield outline identify the cycle. The date letter lookup explains how.
Which other marks appear on London silver?
A full London mark on sterling usually shows four or five punches: the maker's or sponsor's mark, the lion passant for sterling, the leopard's head, the date letter and, between 1784 and 1890, the sovereign's head showing that duty had been paid. Order varies by period and object, so identify each punch by shape rather than position.
The lion passant was added to London marks in 1544 and is explained on the English lion hallmark page. London has also marked gold since the earliest statutes; from 1798 a crown and 18 marked 18 carat gold.
How do you date a piece of London silver?
- Confirm the leopard's head, and note whether it is crowned (before 1821) or not.
- Check for a sovereign's head duty mark, which places the piece between 1784 and 1890.
- Read the date letter with its case, typeface and shield shape, then match it to the London cycle.
- Remember the May changeover: a letter covers late May of one year to May of the next.
Other offices: Birmingham , Sheffield , Edinburgh , Glasgow , Chester , Dublin . All seven compared on the assay office marks page.
Sources
- The Goldsmiths' Company Assay Office: history of hallmarking
- Hallmark, Wikipedia
- London hallmarks and the leopard's head (date tables after Jackson, 1921)
- London date letter charts, silvercollection.it
Frequently Asked Questions
Is the London leopard's head crowned?
Only on pieces marked before 1821. The leopard's head was crowned until that year and uncrowned afterwards. So a crowned head means pre-1821 London work, and an uncrowned head means 1821 or later. Both versions appear with the lion passant on sterling silver.
When did London date letters start?
London date letters began in 1478, when the Goldsmiths' Company set up its assay office in Goldsmiths' Hall. The letter originally identified the assay master sworn in each May, and it advanced each year. London's sequence is the oldest in British hallmarking.
Is the London Assay Office still open?
Yes. The Goldsmiths' Company still hallmarks gold, silver, platinum and palladium at Goldsmiths' Hall in the City of London. It is one of four UK assay offices, with Birmingham, Sheffield and Edinburgh, and since 1975 it uses the same date letter as the other three.
