Mermaids and mermen are mythical creatures with origins outside the classical Mediterranean civilisations. Conventionally, their upper body is human, while below the waist they have the form of a fish. Mermaids seem invariably young, beautiful and buxom, and are most frequently encountered by fishermen and those who go down to the sea. In the Middle Ages they became confounded with the sirens of Greek and Roman myth, who were part human and part bird.

John William Waterhouse’s diploma study for the Royal Academy, painted in 1900, shows a conventional image of A Mermaid, seen combing her long tresses on the shore.

Despite their separate origin, mermaids have been depicted in accounts of some classical myths, perpetuating medieval confusion.

Gustave Moreau’s Venus Rising from the Sea from 1866 shows the goddess as she has just been born from the sea, and sits on a coastal rock, her arms outstretched in an almost messianic pose. On the left, a mermaid attendant holds up half an oyster shell with a single large pearl glinting in it. On the right, a merman proffers her a tree of bright pink coral, and cradles a large conch shell.

Ary Renan’s Charybdis and Scylla (1894) is an imaginative painting of one of the dangers to mariners in the Strait of Messina, between Sicily and the Italian mainland. Scylla was said to be a six-headed sea monster, but was actually a rock shoal, and Charybdis was a whirlpool. Renan shows both together, the whirlpool with its mountainous standing waves at the left, and the rocks at the right, with the form of a beautiful mermaid embedded in them.

As the First World War was ending, Franz von Stuck returned to his favourite faun motif in A Faun and a Mermaid (1918). This has survived in two almost identical versions, the other now being in the Alte Nationalgalerie in Berlin. His version of a mermaid is a maritime equivalent of a faun, with separate scaly legs rather than the more conventional single fish tail. She grasps the faun’s horns and laughs with joy as the faun gives her a piggy-back out of the sea.

Perhaps the earliest painting of a mermaid in European art is in a Christian religious painting by Lucas Cranach the Elder, from 1518-20.

Cranach’s Saint Christopher shows the saint with his back and legs flexed as he bears the infant Christ on his left shoulder. In the foreground is an unusual putto-mermaid with a long coiled fish tail.

Mermaids feature in folktales from many of the traditions of Europe, where they’re known by local names such as havfrue in Denmark.

John Reinhard Weguelin’s watercolour of The Mermaid of Zennor (1900) tells the legend of a mermaid living in a cove near Zennor in Cornwall. This scene brings her together with Matthew Trewhella, a local chorister, whose voice she had fallen in love with. The legend tells that the couple went to live in the sea, and that his voice can still be heard in the cove.

Peter Nicolai Arbo’s Liden Gunver and the Merman (1874-1880) is drawn from an opera The Fishers, by Johannes Ewald and Johann Hartmann, first performed in Copenhagen in 1780. The young woman Liden Gunver, on the right, is taken to sea by the alluring but deceptive merman on the left.

Hans Thoma’s Three Mermaids (1879) lack fishtails as they frolic raucously with fish under the light of the moon.

Gustav Klimt’s Mermaids (Silverfish) (c 1899) appear to be tadpole-like creatures with smiling, womanly faces.

Stories of the abduction of women and their enforced marriage have persisted for an extraordinary length of time. One of the most popular, and still much-loved, musicals is Seven Brides for Seven Brothers, a successful movie in 1954, and as late as 1982-83 it was remade for television. It tells of seven ‘shotgun’ marriages, and was based on a short story The Sobbin’ Women, which in turn was a parody of the story of the rape of the Sabine women in about 750 BCE.

As popular in classical Greek and Roman times was an equally disturbing myth concerning Hypermnestra and her sisters the Danaïds, which was largely forgotten after the Middle Ages, only to be revived around the start of the twentieth century. It was told by Hyginus, Apollodorus, Aeschylus, and Horace, and referred to by many others.

Danaus and Aegyptus were twin brothers who lived in North Africa. Aegyptus was a mythical king of Egypt who had fifty sons, and his brother had fifty daughters, from their polygamous relationships. When Aegyptus decided that his sons would marry his brother’s daughters, Danaus fled with those daughters to Argos, in Greece, where the reigning king generously handed over his throne to him.

Aegyptus and his sons were not to be put off so easily, joined Danaus and his daughters in Argos, and pressed ahead with the plans for the weddings. The couples were assigned by lot, apart from two matches between Hypermnestra and Lynceus, and Gorgophone and Proteus, deemed necessary because of the rank of their mothers, who were princesses.

On the day of their weddings, Danaus equipped his daughters with swords, and told them to murder their husbands in bed that night. Once those drunken grooms had fallen asleep, the daughters each followed their father’s instructions, except for Hypermnestra: by the morning, of the fifty brothers only Lynceus survived.

This story was told in the fourteenth of Giovanni Boccaccio’s De Mulieribus Claris (Concerning Famous Women), published in 1374, and illustrated as Hypermnestra, Lynceus and the Danaïdes (1473) in this hand coloured woodcut from the translation by Heinrich Steinhöwel. Four of the brothers are seen, their throats cut in bed, but the helpfully labelled figures of Hypermnestra and ‘Linus’ are still in a loving embrace.

Robinet Testard shows a similar scene in The Danaides Kill Their Husbands (c 1510), his miniature for Octavien de Saint-Gelais’ translation of Ovid’s Heroides. Hypermnestra’s sisters have each dutifully cut the throats of their new husbands, and sit holding their swords. At the left, though, Hypermnestra and Lynceus sit together on their marriage bed, unharmed.

Danaus was furious with the disobedience of Hypermnestra, who was dragged to a dungeon by her hair to await her fate. It’s at this point that Ovid set his fictional letter from Hypermnestra to Lynceus, the fourteenth letter in his Heroines.

Ovid’s Hypermnestra makes it clear from the outset that she has been charged with the crime of faithfulness, which should surely be praised, not condemned. She reveals the quandary that she found herself in, as she held her father’s sword at the neck of Lynceus and agonised over whether she should kill him or not. Three times she raised the sword in preparation for his murder, and three times her love for Lynceus overpowered her, and spared his life.

Hypermnestra was not summarily executed by her father, but brought before a court, which acquitted her of any wrongdoing. Lynceus (sometimes erroneously named Linus) then killed Danaus, and succeeded him as the King of Argos with Hypermnestra as his queen.

This maiolica plate painted by Francesco Xanto Avelli in 1537 shows the later scene of Hypermnestra Watching Lynceus Take Her Father’s Crown. Lynceus (labelled here as ‘Lino’) has taken Danaus’ crown, and is about to put him to the sword. Hypermnestra stands at a window, most probably not that of a dungeon. Below its lintel is a Cupid bearing the famous saying omnia vincit amor – love conquers all – which actually comes from Virgil’s last Eclogue and is unrelated.

In the end, while Lynceus and Hypermnestra lived happily ever after, the other forty-nine sisters were punished in Hades for the sin of murder. They were given an impossible task, of filling a large container with water; as that container had holes in its bottom, they now spend the rest of eternity carrying water to the container and pouring it in.

Unlike the hapless Sisyphus, who was condemned to push a hefty rock up a steep hill in his Sisyphean task, the Danaïds haven’t been commemorated in figurative language, but have appeared in a surprising number of paintings.

The murderous sisters don’t seem to have had much of a showing in art until Martin Johann Schmidt painted The Labour of the Danaides (1785) on copper. He makes the allusion to Danaïds also being known as water-nymphs, like Naiads, by placing a river god at the left.

John William Waterhouse revived them for two paintings, of which this, The Danaides, was the first, and completed in 1903. He made a second slightly more complex composition in 1906, now hanging in Aberdeen Art Gallery in Scotland. Rather than a battered and leaky barrel, Waterhouse has the Danaïds filling an ornamental cauldron.

I have been unable to find a date for Walter Crane’s version, The Danaides, which was probably for a triptych painted between 1890-1915 and shows a remarkably similar cauldron.

Towards the end of his life, John Singer Sargent painted this vast canvas to show The Danaïdes (c 1922-25), now decorating the entrance to the Library of the Museum of Fine Arts in Boston.

Of all the accounts of this unusual myth, yet again only Ovid looks deep into the relationships involved. He explores the situation of a woman who didn’t commit a crime at her father’s behest, but stayed true to her morals and to her love for Lynceus: a real heroine whose virtue was, for once, rewarded.