What does the date 1742/43 mean? Since around the year 1300, each piece of English silver has been stamped with a series of marks indicating the quality of its metal. Beginning in 1478, the date letter was added to the series as a means of identifying the assay master responsible for testing the article for its silver content. Today, this mark enables us to determine the year in which a piece of silver was made. However, because the date letter is regularly changed each year in the month of May, any given piece was made between May of one year and May of the following year. For this reason, when labeling English silver, a combination date of two years, separated by a slash, is always indicated.