Don Luis gave up the throne of Spain for the woman he loved.
The prince readily avoided the limelight because of his acknowledged big and comprehensive sexual appetite which he exercised with the apparent blessing of his wife.
By the great Czech neo-classical artist Anton Raphael Mengs (1728-1779), it fills a gap in the gallery's portrait holding.
The gallery is also happy that it found a ready donor to pay for it. This is despite a price three times higher than the low estimate.
The gallery acquired donors for the work in Harold and Krystina Campbell-Pretty, whose major business interest has been in Amberley Corporation, a management company.
The gallery's curator of European art, Laurie Benson, told Australian Art Sales Digest that the couple were delighted to have been associated with the purchase.
The couple have made the news for their involvement in the auction process before.
When the couple sold their East Melbourne mansion for $7 million in 2003, surprise was expressed at the difference between the estimate of $4 million to $5 million.
In those days such differences were rare but have become much more common in a world wealth pool that has been much replenished and star lots excite excess.
Their return to the auction process and accompanying philanthropy will be welcomed.
The artist Mengs blended Raphael, Correggio, and Titian in his works, and was once widely considered one of Europe's greatest artists, a position to which he is now returning.
The portrait came to light just as the artist's reputation was being re-established, and appears to be the only Mengs oil in a public collection in Australia.
Another work by the artist has been sold for £134,500 IBP in the same auction house's rooms in London against estimates of £60,000 to £80,000.
The subject is this secular age is of the less colourful subject, John the Baptist preaching. The saint has been more in demand with his head on a platter although contemporary beheadings may have tamed public taste for that particular story.
Mr. Benson told Australian Art Sales Digest that he bid for the Mengs himself over the telephone at 6 am in the morning aware that it could be a while before another work that fitted the bill might come up to auction.
The gallery had lost out to a "museum in San Diego" in a previous attempt to secure another Mengs several years ago.
This work had a good provenance in being recorded in a posthumous inventory of the artist's estate and also appeared in an anonymous sale at Christie's in London in April 1989 when it made £160,000 or $US257,000 at today's exchange rates.
The sitter, Don Luis was the youngest son of King Felipe V of Spain and his second wife, Isabel de Farnesio. His brother died before he was born.
He became cardinal at eight years of age but at 27, conscious of his lack of religious vocation and of his strong sexual drive, he decided to submit his resignation from all his ecclesiastical posts.
Don Luis became the 12th count of Chinchón in 1761; and in 1776, had a morganatic marriage to Maria Teresa de Vallábriga y de Rozas, who was thirty two years younger.
King Carlos III, his brother, had issued a pragmatic sanction by which any royal infant who would marry a person not of royal blood, or whose marriage was not approved by the king, would be excluded from the succession to the throne.
Don Luis has been described as an unfortunate victim of the ambition of his mother and the meanness of the king, who hampered his marriage, fearing problems because his children had been born in Naples, and legally this posed difficulties for the succession to the throne.
He was a major patron of the arts including the musician Luigi Boccherini, architect Ventura Rodriguez and the artist - Francisco Goya.
Dressed in his lilac finery, he is shown with a cheeky air, the sizable canvas posing a sizable challenge to any Australian painting of that price for its value in terms of human interest and, of course, beating them hands down in global significance.
