There are one hundred and fifty-five letters received by Hamilton between 1747 and 1800, together with sixty letters from Hamilton to Sir John Acton (1736-1811), prime minister of Naples, written between 1795 and 1800. Hamilton's correspondents include Earl St. Vincent (q.v.), Viscount Hood (q.v.), John Hampden-Trevor (1749-1824), British minister at Turin, Lord Macartney (1737-1806) and the Marquis of Gallo (1753-1833), secretary of state at Naples. There are also drafts of some of Hamilton's replies.

Administrative / biographical background
Hamilton spent some years in the army before marrying an heiress. From 1764 to 1800 he was envoy extraordinary to the court of Naples. His first wife died in 1782 and in 1791 he married Emma Hart, formerly his nephew's mistress, who had been living with him since 1786. The Hamiltons enjoyed considerable influence with the Neapolitan royal family and succeeded in persuading them to ally Naples with Britain against the French, although this led to the flight of the government to Sicily in 1798 and 1799. In 1800 Hamilton was recalled. He travelled home across Europe with Lady Hamilton and Nelson and eventually settled with them at Merton, where he died.