This is painting as natural philosophy where the background to the holy figures is meant to express the divine as much as the figures themselves. In the same way, the extraordinary tree-root sinews in the neck of the unfinished Saint Jerome (1488-90) were the fruit of the painter's anatomical studies. Rock, flowers, flesh — the origins of each were identical and so was their devotional power.
For divine beauty, however, the real exemplars are his three Milanese portraits: the surprisingly little-known Portrait of a Musician (1485-87) from the Ambrosiana, the portrait of Ludovico's mistress Cecilia Gallerani (The Lady with an Ermine) of 1488-90 from the Czartoryski Foundation in Poland, and La Belle Ferronière (1492-94) from the Louvre. These muted but exquisite works were designed specifically for the eyes of connoisseurs. Leonardo's eschewal of bright colours was deliberate because he believed that "whoever fights shy of shadow fights shy of the glory of art as recognised by noble intellects". The careful modulations of tones and highlights, the imperceptible shifts in flesh and modelling, the careful rendering of texture — all were forms of flattery as well as observational verities.
They were also about a new form of painting. During his Milan sojourn, Leonardo came to believe that art was perfectible and that the aim of painting was to depict everything visible and invisible, from facial features to transitory emotions. It was an extraordinarily exalted ambition and one of the reasons why he so often abandoned works. But the Milan portraits in particular are attempts at taking face painting beyond the depiction of mere physiognomy. They are secular works but these three faces also approach his ideal of harmonious proportion and as such they are imbued with a sense of the spiritual.
In another statement of the ideal, Leonardo defined the painter as "lord of every kind of person and of all things". What this show reveals is that it was an aspiration perhaps only he had the skills and intellect to realise.
