Leonardo had little access to human material when he first started to study anatomy. But in 1489, he obtained a skull, which he cut in a variety of sections to study its structure. In this drawing, he shows the skull sawn down the middle, then across the front of the right side. This beautifully lucid presentation, with the two halves juxtaposed, allows the viewer to locate the facial cavities in relation to the surface features. Leonardo wished to determine the proportions of the skull and the paths of the sensory nerves, believing that they must converge at the site of the soul.
A beautifully rendered study of guelder-rose (Viburnum opulus) has been drawn in red chalk on paper rubbed all over with powdered red chalk. Although it may be connected with Leonardo’s Leda and the Swan, it is far more detailed than necessary as a study for a painting indeed, it surpasses anything found in contemporary herbals. The leaves are shown curling and sagging, for Leonardo was interested not merely in their shape but also in their living form when subject to the natural forces of growth and gravity.
Leonardo’s studies of sleeping cats are among his most sensitively observed drawings and must have been done directly from life. His appreciation of the animals’ lithe forms had a scientific basis, for elsewhere on the sheet he wrote: “Of flexion and extension. The lion is the prince of this animal species, because of the flexibility of its spine.” This suggests that the drawings were made in connection with Leonardo’s proposed treatise on “the movements of animals with four feet, among which is man, who likewise in his infancy crawls on all fours”.
Leonardo drew plants and flowers as studies for decorative details in his paintings and probably also in the process of working towards a systematic treatise on the growth of plants and trees. His finest botanical drawings were executed for his painting Leda and the Swan, which was to have a foreground teeming with plants and flowers, thus echoing the fertility inherent in that myth. The focus of this drawing is a clump of star-of-Bethlehem (Ornithogalum umbellatum), whose swirling leaves are seen in studies for, and copies of, the lost painting.
Leonardo was fascinated by the mechanism of the shoulder and by how the arrangement of muscles and bones allowed such a wide range of movement. Here he analyses the shoulder and arm in a series of drawings at progressive states of dissection. He begins at upper right with the muscles intact and then lifts away individual muscles, such as the deltoid and biceps, to reveal the structures below. At lower right, Leonardo demonstrates the articulation of the ankle with the tibia and fibula lifted away from the foot.
Over the last 15 years of his life, Leonardo worked on a painting of the myth of Leda, showing the queen of Sparta seduced by the god Jupiter in the guise of a swan. The painting was the highest valued item in Leonardo’s estate at his death it later entered the French royal collection but was apparently destroyed around 1700. In this sketch, Leonardo expended little effort on Leda’s demure downward glance, devoting his attention instead to the most complicated of hairstyles – throughout his life he had a love of personal adornment in both hair and clothes.
Leonardo was fascinated by the male profile, both the divinely beautiful and the hideously grotesque. Such heads are found throughout his work, from paintings such as The Last Supper to quick doodles in the margins of his drawings. Towards the end of his life, Leonardo made many carefully finished drawings of classical profiles, exercises in form and draughtsmanship simply for his own satisfaction. Their features – such as the dense mat of curly hair seen here – were inspired by ancient coins and medals of Roman emperors.
Leonardo’s most brilliant anatomical studies were conducted in the winter of 1510–11, when he was apparently working in the medical school of the university of Pavia, near Milan. He may have dissected up to 20 human bodies at that time, concentrating on the mechanisms of the bones and muscles. This is his most complete representation of a skeleton, seen from front, side and back in the manner of an architectural drawing. Leonardo aimed to compile an illustrated treatise on human anatomy, but his studies remained unpublished at his death.
Leonardo’s greatest completed work was The Last Supper, painted in the refectory of the monastic church of Santa Maria delle Grazie in Milan and now in a ruined state. The mural shows the reaction of the disciples to Christ’s announcement of his imminent betrayal. Few drawings survive of the hundreds that must have been made. This study for the head of St Philip, leaning towards Christ in devotion and despair, was probably based on a live model, but Leonardo has idealised the features, taking them out of the real world and into the divine.
Two of Leonardo’s favourite devices – a mysterious smile and a pointing hand – are combined in this ethereal drawing. It shows a woman standing in a rocky, watery landscape, smiling at us while gesturing into the distance, her arms gathering her drapery to her breast. The most plausible explanation is that this is the maiden Matelda gathering flowers, as she appears to Dante on the far side of a stream in Purgatory, the second book of his Divine Comedy. However, the purpose of the drawing is unknown.
Ludovico Sforza, ruler of Milan, commissioned Leonardo to execute a bronze equestrian monument, well over life size, to his father, Francesco. Leonardo’s early studies show Francesco on a rearing horse over a fallen foe. Over the next five years, Leonardo built a full-sized clay model of the horse and prepared a mould for the casting – a huge technical challenge. But in 1494, Ludovico requisitioned the 75 tonnes of bronze for the cast to make cannon, and the monument was never finished. Invading French troops used the clay model for target practice, destroying it.
During the 1480s, Leonardo began to assemble material towards a treatise on the theory of painting. His own paintings, such as the Mona Lisa, were noted even in his own day for their sophisticated treatment of shadows, and here he sets out the geometrical principles of light and shade. The diagram and notes (in mirror writing) explain that where the light falls at right angles on the face, the face will be most strongly illuminated where it falls at a shallow angle, the face will be less strongly lit and where no light is received, under the nose and chin, the surface will be completely dark.