Rescued from its dark banishment in the basement, it now hangs in Room 10 of the National Gallery, surrounded by other Titians and further fine examples of Venetian painting, looking distinctly underwhelming and overpromoted. If this is a Titian, then it is not a very good one.

The first problem is the sitter’s presence, which seems small and standard when compared with the other Titian sitters in the National’s collection. There is none of the psychological force that glues you to the thoughts of the marvellous Man with a Glove on the opposite wall; and none of that fabulously brave picture-making that thrusts an elbow in your face in the nearby Man with a Quilted Sleeve.

The Burlington article admits the painting is in poor condition, which may explain a lot. Much is made of the skill shown by the artist in capturing the textures of the big fur coat, made of lynx, that the putative Fracastoro is wearing. It’s definitely the best bit of the picture. But in the next gallery, in Titian’s superb group portrait of the Vendramin family, the leading Vendramin also sports a coat lined with lynx, and in that instance the painting of the fur is beyond good — it is actually breath­taking. So swift and ­subtle and nuanced.

The single most un-­Titiany thing about the new Titian is its background. The putative ­Fracastoro seems to be standing in front of a grey wall in which we see two peculiar openings: a circular one above his right shoulder and a kind of rect­angular doorway above his left. This weird architectural arrangement appears nowhere else in Titian. The Burlington admits that it cannot be explained by recent overpainting. So why would ­Titian add such a strange background to what is otherwise an unambitious image?

Before it was hauled out of the basement, the painting was attributed to Francesco Tobido, known as Il Moro, who studied under Giorgione in Venice and worked in Fracastoro’s home town, Verona. Though he is largely ­forgotten today, we know that he, too, painted the syphilis doctor. Indeed, the only time I have seen a background like this before was in Il Moro’s portrait of a couple — one of whom is wearing thick fur — that hangs in the Doris Ulmann Galleries at Berea College, Kentucky.

On Waldemar Januszczak's doubts about the Fracastoro portrait attributed to Titian in the National Gallery, and in particular his point about the unusual architectural background: there is, or rather was, a circular window in "La Schiavona", also in the National Gallery, which was painted out by the artist.

Having seen the upgraded painting now myself I agree with your verdict that its condition means the attribution will continue to prove uncertain. Bits of it look good, but its not immediately likeable.