A three-quarter-length portrait to right, seated on a rock at the entrance to a cavern. She wears an ivory muslin dress with a silk shawl tied around her shoulders, a blue green sash around her waist and a wide-brimmed straw hat. Her hands in her lap are joined together and her head is tilted to one side in a gesture of contemplation. The sea is loosely sketched on the right in the background, with the sails of a ship in the distance. The loosely painted portrait gives the appearance of a rapid sketch from life. In the 19th century it became known as 'Lady Hamilton as Ariadne' since it was thought to show Emma posing as this daughter of King Minos of Crete, who helped Theseus to escape from the Minotaur's labyrinth only to be abandoned by him on the island of Naxos. It has more recently been argued that, since Romney probably finished it after Emma left England in 1786, it may rather be a reflection of his own complex feelings for her effective 'banishment' abroad. He still held it at his death, when it was probably the picture listed by one of his assistants as 'Absence', and it was bought in at his studio sale for retention by his son and biographer, John Romney. Emma did, however, pose for several artists as Ariadne, including Elisabeth Vigée le Brun in 1790, and also posed for Romney as Bacchus, who came to Ariadne's rescue.

Emma Hart, born Amy Lyon, was the daughter of a Cheshire blacksmith. After entering domestic service she first became the mistress of Sir Henry Fetherstonhaugh, who mistreated her, and then of the Hon. Charles Greville, who rescued and educated her amid his artistic circle of friends. She was living with Greville, aged nineteen, when this portrait was painted - one of many by Romney, whose favourite model she was, though she was also painted by others. Within three months of sitting for it she left England for Naples and the supposedly temporary protection of Greville's widower uncle, Sir William Hamilton, British ambassador to the Kingdom of the Two Sicilies. Although distressed when she discovered that Greville had in fact permanently 'passed her on' as he tried to court a rich wife, Emma found that Hamilton's kindness and a well-provided lifestyle in Naples under the libertine King Ferdinand IV admirably suited her warm and extravagant personality. She rapidly acquired fluent Italian (with a Lancashire accent) and became famous for her 'attitudes' - solo mime performances based on classical mythology. On achieving formal respectability by her marriage to Hamilton in 1791 she also became an intimate of Queen Maria-Carolina and a notable figure in Neapolitan society. Sir William, one of the great connoisseur-scholars of his time, described her as more beautiful than 'anything found in nature; and finer in her particular way than anything that is to be found in antique art'. The artist's son, John Romney, observed that 'in the characters in which she has been represented, she sate only for the face and a slight sketch of the attitude; and the drapery was painted either from models or from the layman'.

Through Hamilton, Emma first met Horatio Nelson in 1793, a friendship which turned into a mutual passion after he returned wounded to the Hamiltons' care at Naples, after the Battle of the Nile in 1798. From then until Hamilton's death, in 1803, their almost inseparable' ménage à trois 'was sustained by Sir William's urbane refusal to acknowledge the real nature of his wife's relationship with their 'dear friend' Nelson and the lovers' genuine affection for him. In 1801, shortly after they all returned together to England, Emma gave birth in secret to Nelson's daughter, Horatia, around whom they wove an elaborate charade that the child was in fact Nelson's adopted god-daughter. Emma's grief at Nelson's death at Trafalgar in 1805 was inconsolable. She soon ran into debt, for which she was briefly imprisoned, and died in straitened circumstances in Calais in 1815.

The artist was an important portrait painter of the late-18th century, generally ranked third after Joshua Reynolds and Thomas Gainsborough. He was in Paris in 1764 and in 1773 moved to Italy for two years, where he became interested in history paintings in the elevated and élitist 'Grand Manner'. This developed into improving upon nature and the pursuit of perfect form. At its best his work demonstrated refinement, sensitivity and elegance, although it could also be repetitive and monotonous. As a society painter he typified late-18th-century English artists who, compelled by the conditions of patronage to spend their time in producing portraits, could only aspire to imaginative and ideal painting. By 1780 Romney's portraits, according to Horace Walpole, were 'in great vogue' and he worked in an increasingly neo-classical style.