The Virgin of the Rocks is Leonardo's last quattrocento picture

It is an allegro grazioso preluding the adagio of the Virgin of the Rocks; for the later picture is conceived in a mood of great solemnity. The children no longer play as equals. St John kneels in adoration, shielded by the Virgin's cloak, for he typifies the human race in need of protection. Apart from him, and in front of the Virgin, sits the infant Christ, supported by divine inspiration in the form of an angel. His pre-eminence is marked by the two hands which are poised above His head like nimbs, giving Him the isolation of a vertical in the pyramid of the whole composition. He blesses mankind. The angel who, by his glance, invites us to take a part in these mysteries, is himself the most mysterious figure. Why does he point so emphatically at the St John? Towards whom are his eyes directed? We only know that in the more formal London version, where hand and outward gaze are omitted, the picture loses some of its magic. Like deep notes in the accompaniment of a serious theme the rocks of the background sustain the composition, and give it the resonance of a cathedral. Aesthetically their meaning is clear. Have they a further significance? Was Leonardo thinking of some legend of the apocryphal gospels in which the Holy Family during the flight into Egypt seek refuge in a cave and are visited by the youthful Baptist? Behind most of the curious subjects in Renaissance art lie myths and symbols long since forgotten; but in the enthusiasm of discovery their importance can be over-rated. Viewed more closely in the creative process, pictorial symbolism can be a pretext rather than an end in itself, and so the rocks, whatever their apocryphal justification, may have originated in the memory of a childhood expedition to the caves of Monte Ceceri.

The Virgin of the Rocks is Leonardo's last quattrocento picture and still shows the graces of that enchanted interval. Mastery of execution has not overlaid the freshness of the types. The balance between natural and ideal beauty is perfectly held: indeed the process of idealisation has given an added life, as can be seen by comparing the angel's head with the silverpoint study for it at Turin. The drawing--one of the most beautiful, I dare say, in the world--aims at the fullest plastic statement. The painting is sweeter, lighter, more unearthly. This is still idealisation in the Gothic sense. The same is true of the Madonna's head, but here our standard of comparison must be the National Gallery version, which, although not entirely executed by Leonardo, was probably designed by him about twenty years later. In comparing the two heads, the delicate imaginative beauty of the first, the waxen chiaroscuro of the second, we cannot help feeling how far Leonardo's theories of painting led him away from our affections. A comparison of the two children yields the same result. Only in the later angel's head do we feel that Leonardo, by sacrificing freshness to regularity, gained a new quality of classical completeness, though, to our eye, the gain is not worth the sacrifice.

Complementary to this Gothic idealisation is the exquisite naturalism of the details. Hands and feet and hair are observed with a curiosity hardly to be found elsewhere in painting. Leonardo has mastered their structure, but his real delight is in their surfaces, in the delicate skin stretched taut or relaxed into tucks and dimples, with a play of line and light beyond ordinary observation. Similarly, flowers and grasses are depicted with a Gothic understanding of their individual character. They recall the finest carved capitals of the thirteenth century. The Flemish painters, who loved to scatter flowers over their foregrounds, never gave this feeling of growth and inner life, and Leonardo's pupils, who imitated his profusion of plants, could not make them coherent parts of the whole design.

Although the imagery and, to some extent, the details of the Virgin of the Rocks are still perceptible, we must always remember how much of Leonardo's intention is obscured. We can form no real conception of the colour, the values or the general tone of the original, buried as it is under layer upon layer of thick yellow varnish. In the darks some mixture of bitumen has made the surface cake and crack like mud, and there are innumerable patches of old repaint all over the picture. All this must be borne in mind before we say that at this date Leonardo was a dark painter and an uninteresting colourist. Even from its present condition we can see that the Virgin of the Rocks was once remarkably luminous, with a subtle feeling for reflected light; and it is this luminosity which distinguishes Leonardo from his Milanese followers.