A painting attributed to the 15th century Venetian artist Giorgione has been lent to Birmingham's Barber Institute of Arts for the next five years.
The small painting of an unidentified boy is included in an exhibition of portraits which is on display until mid-January.
Giorgione (circa 1477-1510) is the rarest and most mysterious of major Italian Renaissance artists. Only five paintings are definitely known to be by him, and even one of the greatest of them, The Tempest, is an enigma because its subject is unclear.
He is nevertheless regarded as one of the most innovative artists of his time, forming a link in the development of the Venetian School between Giovanni Bellini (whose earliest known painting, coincidentally, is in the Barber Institute collection) and Titian.
The painting from a private British collection which has now been lent to the Barber was previously sold to the Kimball Art Gallery in Fort Worth, Texas, but an application for an export licence was refused.
In the exhibition Face to Face: The Portrait Explored it joins a selection of works from the Barber's permanent collection which explore various approaches to portraiture and aspects of the relationship between artist and sitter.
The latter vary from tradesmanand-client to Royalty-and-servant (Le Brun's chalk drawing of Louis XIV has its first public exposure for many years), or to something more casual, like Derain's painting of the young fellow lodger in a London boarding house who translated for him on a visit to the dentist.
In the case of Bernardo Strozzi's portrait, the unnamed old woman is better described as a subject rather than a sitter, the painting itself a forensic study of old age.
One of the most striking paintings in the exhibition - and apparently the most popular in the collection, surprisingly enough, given the relative obscurity of the artist - is the portrait of the Countess Golovine by Elisabeth Vig>e-Lebrun (1755-1842).
Vig>e-Lebrun, a refugee from the French Revolution, fled from Paris in 1789, settling in St Petersburg six years later.
The sitter, who married into a wealthy family of Moscow aristocrats, also had a colourful life and was the subject of scandalous gossip. Vig>e-Lebrun, who became a friend, described her a charming and talented woman who drew very well and composed delightful love songs which she sang to her own piano acompaniment.
As Barber director Richard Verdi points out, it is rare that the warmth between artist and sitter is as apparent as it is in this work where, 200 years on, Golovine's lively personality still seems uncannily present.
Coincidentally, Vig>e-Lebrun was one of the celebrities who visited Sir William Hamilton, British envoy at Naples, and his wife Emma.
Lady Hamilton, remembered today as Nelson's mistress, would entertain heir guests by posing in a series of classical "attitudes". Two sets of prints recording these, both acquired in the 1960s, are having what is believed to be their first public showing alongside the portraits exhibition. One set, after original drawings by Friedrich Rehberg, is at least intended to be serious but the second, anonymous but probably by the satirist James Gillray, parodies the first while reflecting the fact that Emma put on considerable weight after Nelson's death.
There is an unmissable pre-echo of the modern cult of celebrity here in the public humiliation of a woman always widely regarded as having pretentions abover her station (she was the daughter of a blacksmith): a Regency Posh Spice?
* Face to Face: The Portrait Explored and Nelson's Muse: Lady Hamilton and her Attitudes are at the Barber Institute, University of Birmingham, until January 15 (Mon-Sat 10am-5pm, Sun 12 noon-5pm; admission free).