Antonio Mancini, 'The Marquis del Grillo', 1889

Descended from a grand aristocratic Italian family, the Marquis Giorgio Capranica del Grillo (1849–1922) was a courtier to the Italian Queen Mother, Margherita. The son of an actress, he was an amateur painter as well and moved as easily in bohemian as in royal circles. He was one of many people throughout Mancini’s life who found themselves drawn to this strange and troubled painter, convinced of his artistic originality and determined to help him deal with such practicalities as paying bills and writing comprehensible business letters.

Mancini depicts his 40-year-old patron in the guise of a prince-painter, a type now forgotten but then instantly recognisable. In late nineteenth-century Europe every capital boasted an artist, or artists, who lived grandly, collected with exquisite taste and set the tone for the highest circles of society, like a latter-day Rubens or Velázquez. (In London at the time, Frederic, Lord Leighton, filled the bill.) Here, Grillo poses, easel and brushes in one hand, maul stick in the other, in a corner of his sumptuous studio against a richly worked background of tooled leather. Leopard skins, splendid fabrics and oriental ceramics pile up at his feet while an ebony statue of a young man rises behind him. The camel-skin loincloth suggests it may be the youthful John the Baptist.

Although full-length and grandly formal, the portrait is at the same time intimately nonchalant: Grillo’s legs are crossed, and we even see the sole of one of his shoes. Tiny highlights of paint in each eyeball give a glint of amusement to the marquis’s friendly and tolerant gaze. Subtly worked with rich impasto, this may be Mancini’s masterpiece of the 1880s, when portraiture played an increasing role in his output. In March 1889 Mancini wrote that he hoped to send it to the Universal Exhibition soon to open in Paris, where it would have served as a beguiling advertisement for his portrait skills. In the event, it did not travel to Paris and, for reasons unknown, in about 1904 Mancini post-dated the painting to 1899.

It is also an early example of Mancini’s use of his own curious invention, the graticola, an irregular grid of strings on a wooden frame set up in front of the sitter. Evidence of one such string can be seen in an otherwise unexplained horizontal line across the upper part of the painting. Usually artists used grids to help them accurately record or enlarge details, but in Mancini’s device the strings were haphazard, often running diagonally, creating odd shapes that could only thwart accurate transcription. Mancini said he used it to capture detail and tone on a canvas, but it was incomprehensible to fellow artists.

When the wealthy Irish collector, dealer and curator Hugh Lane had his portrait painted by Mancini in Rome in 1906, he saw this picture in the artist’s studio. His own full-length portrait is not dissimilar in scale and ambition (Hugh Lane Gallery, Dublin) and Lane soon acquired the Grillo portrait. It constitutes a kind of pendant to another life-size portrait of a seated artist in Lane’s collection, Manet’s Eva Gonzalès of 1870, bought in 1906. Lane bequeathed both works to the National Gallery in 1917. Today, display of The Marquis del Grillo is shared between the National Gallery and the Hugh Lane Gallery, Dublin.