Cymon and Iphigenia. Frederic Lord Leighton, P. R. A. (1830-1896). 1884. Oil on canvas, 163.0 x 328.0 cm. Not signed. Not dated. The Art Gallery of New South Wales, Sydney; Purchased 1976 (210.1976). The painting appears here courtesy of the Art Gallery of New South Wales, which retains copyright; it may not be reproduced without the museum's permission.
According to Angus Trumble, Leighton found the subject of this painting in the first story of the fifth day of Boccaccio's Decameron in which the "biggest, strongest and handsomest" son of a nobleman was "a hopeless imbecile" who "became known as Cymon, which means 'the brute.' One day he came upon a young woman fast asleep in a meadow under a tree, and her beauty awakened "his rude soul," at which point he suddenly came to believe, as the English translation of Boccaccio puts it,
that this girl was the fairest creature that had ever been seen by mortal eye. And thereupon he began to distinguish her several parts, praising her hair, which shewed to him as gold, her brow, her nose and mouth, her throat and arms, and above all her bosom, which was as yet in bud, and as he gazed, he changed of a sudden from husbandman into a judge of beauty.
One may add that this parable of beauty soothing the savage breast inverts the standard Victorian cultural myth (painted by Burne-Jones and others) of Sleeping Beauty in which a man awakens a young woman to sexuality and adulthood; in this case, the woman's beauty causes a radical change, a metamorphosis, in the male figure in the story.
The sleeping woman in this erotic painting, Trumble points out, derives from both Renaissance and nineteenth-century paintings: "The dominant, sleeping figure of Iphigenia alludes to famous Italian Renaissance paintings, particularly Giorgione's recumbent Dresden Venus, but is more specifically derived from J. A. D. Ingres's The odalisque and the slave," a study of which the painter had purchased in the 1860s. In addition, like other works by Leighton, Alma-Tadema, Moore, and other classicizing artists of the period, he drew upon ancient art as well:
Iphigenia's complex, swirling drapery was partly the result of the artist's careful study of an ancient Roman statue, the Hellenistic, second-century B.C. sleeping Ariadne or Cleopatra, which was then (as now) installed in the Galleria delle Statue in the Vatican, where Leighton evidently copied it. The essayist Alice Meynell (sister of the artist Elizabeth Thompson), who wrote about Cymon and Iphigenia for the Art-Journal in 1884, drew particular attention to the "eloquence" and expressiveness of Leighton's drapery, arranged here with such swirling profusion over the sleeping Iphigenia. 
In addition, Leighton made great use of color, for
The erotic effect of the group is enormously enhanced by the colouring — the warm yellows, oranges, reds and ochres — made possible by adjusting the time of day. According to Leighton's biographer, Mrs Russell Barrington, the artist chose to represent "the most mysteriously beautiful in the whole twenty-four hours, when the merest lip of the moon has risen from behind the sea horizon, and the air is haunted still with the flush of the after-glow from the sun already hidden in the west." Later in his career, Leighton would concentrate on more and more astonishing effects of natural light, in both versions of Clytie, for example. 
Trumble, Anglus. Love and Death: Art in the Age of Queen Victoria. Exhibition catalogue. Adelaide: Art Gallery of South Australia, n.d.
Last modified 4 December 2005