Pierre Mignard, 'The Marquise de Seignelay and Two of her Sons', 1691

Painted towards the end of Mignard’s career, this is a portrait of Catherine-Thérèse, the Marquise de Seignelay (1662–1699), and two of her five sons. She was the widow of Jean-Baptiste-Antoine Colbert (1651–1690), the Marquis de Seignelay and eldest son of Jean-Baptiste Colbert (1619–1685), the most powerful minister in seventeenth-century France.

The Marquise and her children are painted as characters from Greek and Roman mythology. She is probably meant to be the sea goddess, Thetis. She could also be interpreted as Venus, the goddess of love and beauty, with her attributes of a scallop shell and strings of pearls. One of her children is dressed as the winged Cupid, the god of love, who kneels beside her carrying arrows. The other is shown as Achilles, a Greek hero of the Trojan War, his ornate armour, scabbard, helmet and shield reflecting his military skill. Achilles was usually portrayed as a mature warrior but this has been ignored given the age of the child – probably Catherine-Thérèse’s eldest, Marie-Jean Baptiste.

The figures‘ clothing is rich in detail. Catherine-Thérèse wears a gold-embroidered gown, with a jewelled belt and sandals. Her robe was painted using an expensive, high-quality ultramarine blue, as a show of her wealth and power; the amount of pigment used was unusual during this period. She holds a small cameo adorned with a portrait. Its importance shown by the way the children gaze towards it – perhaps it is of her husband, who had died a year earlier. The red coral in Cupid’s shell and in Catherine-Thérèse’s hair symbolises the power to heal and protect. Many of the symbols reflect the importance of family relationships.

Shells are scattered at the water’s edge, celebrating Seignelay’s career in the French royal navy and his famed collection of rare objects. The figures are surrounded by sea and a smoking volcano – perhaps Vesuvius, which Seignelay had witnessed on his travels to Italy.

This was painted in 1691, the year after Mignard became the official painter to King Louis XIV and senior official at the Académie Royale, positions formerly held by his great rival, Charles Le Brun (1619–1690). In 1914, on seeing the painting in Paris, the then Director of the National Gallery, Charles Holroyd, observed that it was ’a large cold picture dull in composition & colour but well painted... I recommend that it be declined. If accepted, it could only be hung downstairs' – presumably where fewer visitors would see it.