There is an old tradition mentioned by Vasari, that charming gatherer of legends with regard to the old painters, that Leonardo, unable to satisfy himself with the head and face of Jesus, left it unfinished. This would indeed have been a sad loss to art. Leonardo hesitated for long, wondering above all whether he should follow a model, but finally made his peace with tradition, accepted the type of head for the Lord that had been created by Giotto, and refining it still more succeeded in giving a look of mystic superhumanity to it that would evoke the idea of divinity. It is easy to see how much he borrowed but it is harder to realize how much he added, yet artists who have studied it have felt that here indeed was a triumph and that, as far as possible, Leonardo had represented the human face divine. He followed his model strictly in the case of the Apostles' heads and none knew better than he how to select models, but in the head of Christ he turns from the model and works out his design from ideals of the human face of which so many existed in his well-stored fancy. The face of Christ was left somewhat vague, trembling, undissolved like faces seen in cloud or in the fire. Leonardo himself once counselled his students to look for suggestions in curious cloud and fire shapes and even to study the vague forms that occur in imitation of human faces on cracked and stained surfaces of ruined walls, and some of his own devotion to this seems to have been of help to him in this marvellous face. {18}