English: Sir Peter Lely (Soest 1618 - 1680 London)

Portrait of a lady, said to be Lady Diana Sidney (c. 1628–1670)

inscribed lower left: LADY DIANA / SIDNEY / DAUGHTER TO / ROBERT EARL / OF / LEICESTER

oil on canvas

125.1 x 102 cm.; 49¼ x 40⅛ in.

This particularly shimmering pastoral portrait by Sir Peter Lely dates to the late 1650s. Furthermore, it is presumed to share the same Cassiobury Park provenance as Lely's Portrait of Elizabeth Capel, Countess of Carnarvon (1633–1678), with a guitar sold in these rooms in 2021.

This painting exemplifies Lely's mature style, in which no expense is spared on painterly details. The artist's quick and nervous brushwork is evident throughout the canvas, particularly in the sitter's remarkable dress. The rusty orange and red tones of the clothing complement the setting behind, which features a particularly fine bucolic landscape. Lely's subtle colouring and evocative brushwork in the trees, sky and meadow behind are captured in a way that wouldn't have been entirely unfamiliar to artist John Constable (1776–1836) centuries later. Diana Dethloff has connected the arms and hands of the sitter in this portrait to a study in chalks preserved at the Metropolitan Museum of Art, New York, which adds further interest to the methods employed by Lely to complete such commissions.

Research into the provenance of this painting shows that the portrait was hanging alongside Lely's Portrait of Elizabeth Capel, Countess of Carnarvon (1633–1678), with a guitar at Naworth Castle in 1904 (fig. 2).2 This is significant, as the Capel portrait has been traced back to an important commission for Cassiobury Park, Hertfordshire, the home of Arthur Capel, 1st Earl of Essex (1632–1693). The painting may have also once been part of the celebrated group of family portraits by Lely, which have since been scattered amongst museums and private collections. In the early eighteenth century, the diarist George Vertue remarked of this striking group, following a visit to Cassiobury, that they were ‘of the best and highest perfection that I ever saw painted by Sr. P. Lelly especially so many & so compleat together – not excepting the Beauties at Windsor which I have seen more than once’.3 Portraits that have been traced to Cassiobury include Lely's double portrait of Lady Elizabeth and Lady Mary Capel and Lely's Portrait of Sir Henry Capel, in a similar Sunderland frame, both of which survive at the Metropolitan Museum of Art, New York.

If the inscription on the painting is to be believed, then this portrait depicts Lady Diana Sidney (c. 1628–1670), one of the younger daughters of Robert Sidney (1595–1677), 2nd Earl of Leicester, and his wife Lady Dorothy Percy (c. 1598–1659), the daughter of Henry Percy, 9th Earl of Northumberland. Diana never married, and very little is known about her life. This raises the question as to whether this later identification might be erroneous. Lely captured several portraits of young men said to be Diana's brothers Philip (1619–1697), Algernon (1622/3–1683) and or Robert (1626-1668).

There also seems to be at present no clear connection between Diana and Arthur Capel, 1st Earl of Essex (1632–1693) (eight creation), who is said to have commissioned the portraits for Cassiobury Park. It may have been political allegiances that saw the commissioning of this portrait, as the Sidneys were amongst the most important English aristocratic families of the seventeenth-century.