St John the Baptist was painted by Leonardo da Vinci between 1513 and 1516, when the High Renaissance was turning into Mannerism. It is thought to be his last painting. It is an oil painting on walnut wood. The original size of the work was 69x57 cm.
The gesture of St. John pointing to the heavens suggests the importance of salvation through baptism that John the Baptist represents. The work is often cited by later painters, particularly those of the late Renaissance and Mannerist schools. The inclusion of a gesture similar to that of John would increase the importance of the work to the religious conception.
Many critics of the work see it as a disturbing depiction of a figure normally portrayed as emaciated and fiery, living in a desert and surviving on a diet of locusts and honey. In Leonardo's painting, St John seems almost a hermaphrodite. He has a woman's arm folded across his chest, his finger raised to the sky, and the same enigmatic smile that we see on Mona Lisa's face, a smile that we see in other paintings by Leonardo, such as that of Saint Anne. Her face, almost like that of a faun, is framed by a glorious cascade of curls. The finger pointing to heaven appears quite often in Leonardo's work (the Burlington House caricature is another example) and denotes the coming of Christ.
Leonardo was aware of the dangers inherent in this system. Earlier in his notes he warned that a figure will not be discernible against a dark background and will not appear to stand out. From a distance, only the illuminated parts will be seen. However, in the shadows of the body of St John the Baptist, Leonardo has retained just enough light for us to fully grasp his form. As in the moon, even the dark areas of his figure retain a slight glow of reflected light.
This is the last known major work by Leonardo's hand. The haunting beauty of the figure comes from the ambiguity of its sexual identity. The luminous face seems to be an emanation of the darkness that completely envelops it. The mysterious gesture of the raised arm with a finger pointing upwards has not only a religious but probably also an esoteric meaning.