Robert Hennell III was part of the large Hennell silversmith family in London. When his father Robert Hennell II retired, Robert III entered his first mark in 1834.
The census of 1851 describes him as a silversmith aged 56 employing nine men and his wife Jane with his four sons: Robert (IV) a silver chaser, James Barclay, a silver plate worker, Charles (6 yrs) and Percy (4 yrs).
Robert III died in 1868 and his sons Robert (IV) and James Barclay took over the family firm. Robert III worked in the styles popular at the time, particularly using forms copied directly from nature. The V&A Museum in London have some of his work on display.
The founder of "Hennell dynasty" was David Hennell (I) (1712-1785), apprenticed to Edward Wood in 1728. David Hennell obtained his freedom (1735) and opened his own business in Gutter Lane in 1736.
In 1763 he was joined in the business in Foster Lane workshop by his son Robert (I) (1741-1811), entering a joint mark in 1763 and 1768. David Hennell retired in in 1773 c. and the family business was continued by Robert Hennell (I).
In 1795 David Hennell (II) (1767-1829) entered in partnership with his father registering a new conjoined mark (Robert Hennell (I) and David Hennell (II).
In 1802 his brother Samuel Hennell (1778-1837) joined to the partnership but soon after David Hennell II retired from the firm and the business was continued by Samuel Hennell and his father Robert Hennell (I).
After the death of his father (1811) Samuel Hennell took over the business forming a brief partnership (1814-1816) with John Terry who had married one of his nieces. In 1816 Samuel Hennell returned to working on his own.
Robert Hennell (II) (born 1763) was the nephew of Robert Hennell (I). He was apprenticed in 1778 to his uncle and to John Houle (engraver). He obtained his freedom in 1785 probably working only at engraving until 1808 when he entered in partnership with Henry Nutting. The partnership lasted until 1809 when Robert Hennell (II) entered a mark by his own (35 Noble Street, Foster Lane).
In 1817 the firm moved to 3 Lancaster Court, Strand and to 14 Northumberland Street, Strand in 1828. In 1817 c. his son Robert Hennell (III) (1794-1868) joined the firm Robert Hennell & Son and after the retirement of his father (1833) took over the family business. Two of the sons of Robert Hennell (III) were apprenticed to their father: Robert Hennell (IV) (1826-1891), apprenticed in 1842, free 1849, and James Barclay Hennell (1828-1899), apprenticed in 1843, free 1850.
In 1868, at the death of Robert Hennell (III), the firm was taken by his two sons Robert Hennell (IV) and James Barclay Hennell. Robert Hennell (III) retired in 1877 and James Barclay Hennell continued to manage the business by his own until 1887 when the firm was sold to Holland, Aldwinckle & Slater.