The Dublin Assay Office was established in 1637 to supervise the assaying of all gold and silver throughout the whole kingdom of Ireland. Originally, hallmarks consisted of the goldsmiths' proper mark which was the maker\'s mark originally used to identify the silversmith or goldsmith responsible for making the article. The fineness mark, the harp crown was applied to 22 carat gold and sterling silver, which was silver of a standard of 925 parts of fine silver in each 1000.
In 1638 a date letter system was introduced and used in conjunction with the above marks. This date letter denotes the year in which the piece was made or hallmarked and is changed on January 1st each year. A new mark in the form of Hibernia was introduced on March 25th 1730 to indicate that a duty had been paid on all articles manufactured on or after that date. The Hibernia mark is used on all articles of Irish manufacture hallmarked at the Dublin Assay Office.
Through three and a half centuries the Goldsmiths Company has afforded a high degree of consumer protection. The term 'hallmark' has come by common usage to connote a degree of quality or standard that is generally recognised.