In the Wildenstein version the table is covered with a carpet and extended forwards to hold a tenor recorder, while the still life is replaced by a spinetta (a small keyboard instrument) and a caged songbird.

The Wildenstein version shows songs by a native Florentine (Francesco de Layolle) on a text by Petrarch: Laisse le voile ('Let go the veil') and Pourquoi ne vous donnez-vous pas?

The rather androgynous model could be Pedro Montoya, a castrato known to have been a member of the Del Monte household and a singer at the Sistine Chapel at about this time – castrati were highly prized and the Cardinal was a patron of music as well as of painting.

[2] Such a complex illustration of refracted light is unprecedented in the Cinquecento, and may have been the result of collaboration with scientists in Del Monte's circle, including Giovanni Battista della Porta, who was the guiding spirit behind the foundation in 1603 of the Accademia dei Lincei.

The circle of Della Porta was significant for Caravaggio later on in Naples, where the commission for the Seven Acts of Mercy seems to have emanated from Giovanni Battista Manso, Marchese di Villa, whose friend, the alchemist Colantonio Stigliola, was a member of the Accademia dei Lincei.

The procedure for making a second version was, however, substantially different from the sometimes very arduous task of building a group from many separate observations of reality, of figures and objects; it is natural that the 'second original' is sometimes more fluent than the first.

The Wildenstein version was sold by Del Monte's heirs to Cardinal Antonio Barberini in 1628, when it was described as "Un giovane che sona di clevo" (without an attribution) and included with St Catherine and the Cardsharps (named specifically as by Caravaggio) and various other paintings.

Nevertheless, critic Jason Kaufman felt that the rendition of the boy in the Wildenstein version was aesthetically inferior to the Hermitage, "...the face...hard and the expression less sweet than bovine...[t]he features...more sharply defined, the eyebrows severely geometrized, and the complexion pink, rather than fleshtone, " and David Van Edwards, noting apparent mistakes in the depiction of the lute in the Wildenstein version, the secondary light source and the inconsistent perspectives of table and sitter, concluded that the painting is not by Caravaggio.

Del Monte's interest in this is manifest in the group of portraits that hung in his alchemical Casino, which are of the same seven luminaries who are illustrated in the titlepage of Oswald Croll's Basilica Chymica (Frankfurt, 1609).

We know that the Casino on the Pincio was the centre in Rome of the practice of iatrochymia or chemical medicine, although this kind of natural philosophy was increasingly frowned on and may well have played a part in the damnation memoriae that Del Monte was subjected to.

It appears likely that the Lute Player was originally intended as a decoration for the studiolo on the first floor of the Casino on the Pincio that Del Monte had acquired in 1596, and where Guercino would later paint his fresco of Aurora for the Ludovisi.

On the ground floor Del Monte did his alchemical work and chemistry; above, on the ceiling of the studiolo, Caravaggio painted the gods Neptune, Jupiter and Pluto, representing the Elements.

Since Giordano Bruno had written that it was appropriate to represent Apollo, ever-youthful, playing the lute, as opposed to his more conventional lyre, this may have been Del Monte's intention in this painting, and the rays of sunlight that are such a feature of the glass sphere have this meaning.

There was such a picture, painted for the Mattei family and later also bought by Cardinal Pio from the Del Monte collection, an oblong composition with St John playing with a lamb, and with a reed cross on his shoulder, that was eventually sold to Gavin Hamilton in 1777.

Elements of the composition of the Apollo Lute Player are repeated not only in the Hermitage work (with several counterpoint variations), but also in the glass carafe in the lower part of the two paintings A Boy bitten by a Lizard, most especially in the version in the National Gallery, London.

It is interesting that he would devote such care to a painting of flowers, as he did also to the Basket of Fruit in the Ambrosiana, and that he was not averse to doing this, as is illustrated by the fact that he introduced the carafe of water with the same reflections into the canvases of the A Boy bitten by a Lizard, without regard to the position of the figure in front of the light sources.

The parabolic mirror, probably the same one that Della Porta had had constructed in Venice in 1580, which had produced some sensational effects and led to the development of the camera obscura, was probably no larger than an eye-glass, but it made it possible to make a mosaic of naturalistic images that was extremely compelling; the technique also explains the shallow focus of Caravaggio's compositions.