The centre section of the roundel – the area containing the image of the saint, not the frame – is said to be an earlier work attributed to the Sienese painter Bartolommeo Bulgarini and which was later recessed into the main panel by Botticelli. But there is no definite proof of this and the saint has never been identified.

Taking into account that the figure of the young man is Piero de Lorenzo di’ Medici and modelled on Donatello’s Marzocco lion, the roundel therefore represents a shield, a symbol of both protection and identity. However, in this instance the roundel seemingly has no connection to the style of shield or the red lily emblem associated with Florence. Instead Botticelli has subsituted references to Siena, a rival neighbour south of Florence, noted for its saints and preachers.

The most obvious reference is the colour of the frame – burnt sienna – derived from an earth pigment known as terra di Siena and sourced from the region during the Renaissance. Yellowish-brown in its raw state, it turns to reddish-brown when heated and is then referred to as burnt sienna. The heating or conversion process is implied by the fiery colours used as the base for the saintly portrait.

This section of the painting represents two of the classic four elements in Greek philosophy – Earth and Fire. The two other elements are Air (the heavenly sky background) and Water (the colour of Piero’s deep blue tunic).

Sotheby’s auction catalogue states “the saint lacks any identifiable attributes, and only his right hand is visible, raised as an apparent gesture of blessing”. However the ‘sign of the horns’ is an attribute which can be identified with two particular saints – Moses, and his assistant Hoshea whose name was later changed to Joshua. So is the saint in the roundel, Moses or Joshua? Perhaps the figure is meant to represent both, as well as other biblical prophets and preachers.

There are other themes incorporated in the roundel to suggest it was produced by Botticelli during Piero’s time and is not the work of the Sienese painter Bartolommeo Bulgarini. This is borne out by several references to the roundel, Siena, and Botticelli in the Parnassus painting by Andrea Mantegna.

An earlier Sienese painter most likely to have inspired the style of roundel replicated by Botticelli was Duccio di Buoninsegna (d.1319). One of his most famous works is the Maestà commissioned by the city of Siena in 1308. The front of the the altarpiece depicts the Virgin Mary and Child enthroned, surrounded by numerous angels and saints. The predella is a series of panels depicting the Childhood of Christ, interspersed with images of six prophets.

It is a section of this predella that was the lkely source for Botticelli and his portrait of a Young Man Holding a Roundel. The scene illustrates the Flight into Egypt of the Holy Family. Left of the scene stands the ‘weeping prophet’ Jeremiah (B), and on the right is the prophet Hosea (D) showing the ‘sign of the horns’.

Another work partly attributed to Duccio is an altarpiece referred to as Polyptych No. 47, again featuring the Virgin with Child accompanied by angels and prophets. Above the Virgin is a panel depicting Moses (C), his left hand displaying the “sign of the horns”.

Was this portrait of Moses (C) the basis for the saint (A) shown in the roundel? If so, what connection was Botticelli making to want to link Moses, or any other ‘prophet’ it represented, with Piero?

• More on this in a future post…