Pinacoteca art gallery, Room IX: St. Jerome in the Wilderness by Leonardo da Vinci

The attribution of the work proposed by Kauffmann has always met with the agreement of scholars due to the obvious similarities to the other works of the maestro and in particular the Adoration of the Magi (Florence, Uffizi Gallery).

The painting depicts Saint Jerome during his retreat to the Syrian desert, where he lived the life of a hermit. St. Jerome kneels in a rocky landscape, gazing toward a crucifix which can be discerned faintly sketched in at the extreme right of the painting. In Jerome's right hand he holds a rock with which he is traditionally shown beating his chest in penance. At his feet is the lion which became a loyal companion after he extracted a thorn from its paw. The lion, the stone and a cardinal's hat are the traditional attributes of the saint.

On the left-hand side of the panel the background is a distant landscape of a lake surrounded by precipitous mountains shrouded in mist. To the right-hand side, the only discernible feature is a faintly-sketched church, seen through the opening in the rocks. The church's presence may allude to Jerome's position in Western Christianity as one of the Doctors of the Church.

The composition of the painting is innovative for the oblique trapezoid form of the figure of the saint. The angular forms contrast with the sinuous form of the lion which transcribes an "S" across the bottom of the painting. The form of St. Jerome prefigures that of the Virgin Mary in the Virgin of the Rocks. The anatomy of the saint relates to a page of anatomical drawings of the shoulder girdle.

The panel has been reduced in size and the remaining part was cut in two at some point in its history and was reassembled for the early 19th-century collector, Cardinal Fesch, the uncle of Napoleon Bonaparte. Popular legend has it that the Cardinal discovered the part of the panel with the saint's torso being offered as a table-top in a shop in Rome. Many years later, he found another piece being used as a wedge for shoemaker's bench. Whatever the circumstances of Fesch's finding the parts, the repaired panel was sold by his descendants to Pope Pius IX, who installed it in the Pinacoteca Vaticana, now part of the Vatican Museums. The St. Jerome was once believed to have been part of the collection of the painter Angelica Kauffman, but this theory too has been rejected by recent scholars.

No information is available as to the destination of the painting and who it was commissioned by. Still in the sketch state it is one of the most enigmatic works of the great Tuscan painter, sculptor, architect, engineer and philosopher. The earliest mention of the St Jerome dates in fact to the beginning of the 19th century, when it is attributed to Leonardo, in the will of the Swiss painter Angelica Kauffmann. On Kauffmann's death all trace of it again disappeared, until it was found by chance and purchased by Napoleon's uncle, Cardinal Joseph Fesch. According to tradition the cardinal discovered the painting divided into two parts: the lower part in the shop of a Roman second-hand dealer where it formed the cover of a box, and that with the head of the saint at the shop of his shoe-maker who had used it to make the cover of his stool. Over and above the story, the painting can really be seen to be cut into five parts. On the death of the cardinal the picture was auctioned and sold a number of times until it was identified and purchased for Pius IX (pontiff from 1846 to 1878) for the Vatican Pinacoteca (1856).