Giovanni Battista Tiepolo, 'A Vision of the Trinity', about 1735-9

This small oil sketch or modello relates to an altarpiece that Giovanni Battista Tiepolo painted for the chapel at the palace at Nymphenburg, outside Munich, in around 1735 (now in the Alte Pinakothek, Munich). It was made so the patron could see what the altarpiece would look like, but it’s so highly finished that it can be regarded as a complete work of art in its own right. The final version was among the first paintings by Tiepolo to reach Germany; he spent the majority of his career working in Venice and elsewhere in Italy.

It was probably commissioned by the Archbishop-Elector of Cologne, Clemens August, which would explain the presence of Saint Clement, his namesake, who kneels in the foreground, a vision of the Trinity above him. He is outlined against a great coffered semi-domed room, and the Trinity in the upper right push forward from a cloudy sky. Here, as in many of Tiepolo’s altarpieces, a pale light pours in through the classical arch in the background, drawing our eye towards the action in the foreground. God the Father and Christ, who wears a shroud and holds the Cross, are seated on a cloud, its graceful curve much like that of the classical arch. The dove of the Holy Ghost hovers next to a frenzy of cherubs, who gaze intently towards God the Father and Christ. A winged angel with a three-barred patriarchal cross sits upon the altar steps, following Saint Clement’s gaze.

Tiepolo was celebrated for his use of colour and light. Here, swathes of bold primary colours – the red of the carpet, the yellow gold of Saint Clement’s vestment and the blue of the angels' draperies – mark the earthly, holy and celestial parts of the painting. These colours are offset by the tiny, sparkling decorations on the silver censer, which was used to burn incense during religious worship, at the bottom right. A silvery cloud carries the holy figures upward in a spiral of movement. The kneeling saint, too, appears to be moving upward, towards his vision. The effect is both highly dramatic and elegantly refined.

The artist made several changes to the composition of this sketch, the most significant being in the figure of Saint Clement: he was initially taller and did not raise his head towards his vision. There are very few changes between this modello and the altarpiece, though in the latter the frame obscures the statue of Faith carrying the Bible and holy cross.