In 1773, Sheffield's silversmiths joined with those of Birmingham to petition Parliament for the establishment of Assay Offices in their respective cities. In spite of determined opposition by London silversmiths, an Act of Parliament was passed in March, just one month after the original petition was presented to Parliament, to allow Birmingham and Sheffield the right to assay silver.
The Assay Office was then founded and hallmarked its first piece on 20 September, 1773. Lots were drawn to determine which marks the offices would use. Sheffield won and chose the crown, while Birmingham took the anchor. Originally, only silver produced within twenty miles of Sheffield could be marked at the office. From 1784, Sheffield was empowered to keep a register of all maker's marks within one hundred miles, including those of Birmingham.
In 1795, after several moves, an office was established on Fargate. In 1880 it moved to Leopold Street, and in 1958 to Portobello Street. In May 2007 it was announced that the office would move to a new purpose built site on Beulah Road by Summer 2008. In 1977, Sheffield's mark was changed to the Yorkshire Rose, and it became the last office to standardise its date letters.