George Nassau (1756-1823) was an English country gentleman, and the brother of Henry, 5th Earl of Rochford. He was a historian and bibliophile and amassed an extensive library including many manuscripts on his home county Suffolk, with illustrations commissioned by him from leading artists of the time such as Thomas Gainsborough. His will notes that on his death, the following people were to receive mourning rings, valued at six guineas each: Reverend H.I. Berners, Sir William Rowley, John Wright Esq., Reverend William Gibson, Sir William Parker Bt., Sir Francis Hilman, Captain Hopkins, Reverend William Garratt, William Berners Esq., Reverend Dr Kilderlee, Colonel Dupuis, John Phillips Esq., Sir Robert Spencer Kilderlee Esq., James Saicer Esq., James Wenn Esq., Earl Ludlow, George Farrant Esq., John Butler Esq., and Reverend Samuel Jones Knight.
One other of George Nassau's commissioned mourning rings can be seen in the V&A Museum's collection, reference M.168-1962.
The abbreviation 'ARM' stands for the word 'armigerous' which meant that a person was literally a bearer of weapons or armour and thus entitled to use a coat of arms. In more modern terms, it means that you are entitled to call yourself 'Esquire'.