I buy and sell a lot of antique silver and I am often asked how to accurately date it. The first thing to look for is the hallmark. Most silver pieces will have a hallmark, although marks will be different for continental pieces. Look for the Lion Passant - this is the British sterling silver mark which tells you the piece has been tested for purity and is .925 sterling silver.
Generally speaking hallmarks have 4 parts, the Lion Passant, the town mark where it was assayed, the date letter for the year it was made and finally the maker’s mark.
Some of the biggest silver assaying offices are in London and Birmingham, London marked by a Leopard’s Head and Birmingham by an Anchor. People often wonder why Birmingham, a completely land-locked city is represented by an anchor and it’s quite an interesting story. In 1773, before the inauguration of the Birmingham and Sheffield Assay Offices, a meeting was held in London at a public house called The Crown and Anchor Tavern. The choice of symbol was supposedly made on the toss of a coin which resulted in Birmingham using the Anchor and Sheffield using the Crown. We can be sure a few pints of Ale were also involved in the decision making process!
Some smaller towns also assayed silver for a short time. One particular mark to look out for locally is the Exeter town mark - a castle with three turrets. The assay office officially opened in 1701 and closed down in 1883 and some pieces can be quite rare because it operated for such a short time.
Once you’ve determined the town that the piece was assayed in, the corresponding date letter will tell you the year in which it was made.