There is contemporary or near contemporary authority for four types. All are undated, but an approximate chronological order based on dress and apparent age would be as follows. Probably in the second decade of the century, a youthful looking half length, engraved by J. Heath
for Horace Walpole's collected works, 1798, the artist and source of the original not stated. 
The style suggests Jervas and the features agree with the next portrait, listed in the Round Bed Chamber at Strawberry Hill by 1784: 'Henrietta Hobart countess of Suffolk, sitting; a view of her house at Marble-hill, Twickenham: by Jervas. It was Mr. Pope's: lady Suffolk bought it at Mrs Martha Blount's sale, and gave it to Mr Walpole.' 
Bought by the Earl of Buckinghamshire 
at the Strawberry Hill sale, 21st day, 18 May 1842, lot 4, it was lent to the NPG by his descendant's executors 1953-7, NPG 3891. Mrs Martha Blount (1690-1760) was a constant companion and neighbour of the sitter. No sale catalogue is recorded, but there seems little reason to doubt the provenance. 
The topography however presents more of a problem. Although there is a low Palladian building reminiscent of Roger Morris's design for Marble Hill, 1723-29 
and the river was then tidal, the background does not much resemble the Thames at Twickenham, even seen from Richmond Hill. It is necessary to account for the large bluff, and even more for the large square keep-like building with turrets at the corners. Jervas seems to have taken a good deal of licence. 
At any rate it is not Blickling. If Marble Hill is depicted, the house was standing by c
.1725, which would be a reasonable date for the painting. About this time comes the Blickling portrait discussed under NPG 2451
. Fourth, Walpole saw in 1768 a miniature portrait at Adderbury, Oxfordshire, then a Buccleugh seat: it is perhaps the square miniature lent by the then Duke to the Manchester exhibition 1857. 
Lady Suffolk also figures in Charles Philip's 'Tea Party at Lord Harrington's House', 1739, in the Paul Mellon collection. 
The sitter, often known as Mrs Howard, may well be represented in the mezzotint by J. Faber junior
so lettered after a painter I, (or J) Peters (J. Chaloner Smith, British Mezzotinto Portraits, 1878-83
, 194), not now identified. The identification which relies on comparison with authentic portraits is plausible, but there are other contemporary possibilities, discussed by Chaloner Smith. A portrait stated to represent Lady Suffolk as Mary Magdalen by Jervas was formerly (1878) in the collection of the Earl of Carnarvon at Highclere Castle, Hants. 
1) The Works of Horatio Walpole, Earl of Orford
, 1798, V, opposite p 75.
2) A description of the Villa of Mr. Horace Walpole ... at Strawberry Hill ...
, 1784, p 80.
3) The 1st Earl was the sitter's brother.
4) There was another picture in the Round Bed Chamber from Lady Suffolk's sale, 'Henrietta duchess of Orleans, as Pallas; bought at lady Suffolk's sale'. A description of the Villa of Mr. Horace Walpole ... at Strawberry Hill ...
, 1784, p 80.
5) H. M. Colvin, A Biographical Dictionary of British Architects
, 1954, p 396.
6) Information kindly given by Messrs E. Croft-Murray and J. Jacob. Mr John Harris suggests the Severn may also be intended, Thomas Wright being employed on Gothic designs for Berkeley Castle in the late 1730s.
7) Sir George Scharf's Sketchbooks, vol.48, p 76. No.14 Frame, Transept Gallery, British Portrait Gallery of the Manchester exhibition.
8) Exhibited 'Painting in England 1700-1850', Richmond, Virginia, 1963, p 116.
9) NPG archives.This extended catalogue entry is from the out-of-print National Portrait Gallery collection catalogue: John Kerslake,
Early Georgian Portraits, Her Majesty's Stationery Office, 1977, and is as published then. For the most up-to-date details on individual Collection works, we recommend reading the information provided in the Search the Collection results on this website in parallel with this text.