Miniature of Ferdinand IV, King of Naples and Sicily, sometimes called 'the Golden Monarch' and more commonly King of the Two Sicilies, the latter well before he formally adopted that title in 1816. It is executed in watercolour, probably on ivory, and is inscribed on the right edge 'Biaggio di Costanzo'. The reverse is inscribed with the initials 'NW', the whole being contained within a blue and white enamel frame.

Ferdinand's kingdom, especially Naples, proved a valuable foothold for British Mediterranean operations from the start of the French Revolutionary War in 1793 until it was annexed by Napoleon in 1806. His much more astute and domineering queen, Maria-Carolina, was a daughter of the Empress Maria-Theresa of Austria and sister of Queen Marie-Antoinette of France who had been beheaded in 1793. The court at Naples and at their Sicilian capital, Palermo, was characterized by display and extravagance. Though popular with the Neapolitan mob, Ferdinand was mainly interested in hunting and the Queen was the controlling influence in government, manipulating Nelson through her friendship with Lady Hamilton.