In mentioning the concurrence in Leonardo of the powerful investigation impulse with the stunting of his sexual life which was limited to the so-called ideal homosexuality, we feel inclined to consider him as a model example of our third type. The most essential point of his character and the secret of it seems to lie in the fact, that after utilizing the infantile activity of curiosity in the service of sexual interest he was able to sublimate the greater part of his libido into the impulse of investigation. But to be sure the proof of this conception is not easy to produce. To do this we would have to have an insight into the psychic development of his first childhood years, and it seems foolish to hope for such material when the reports concerning his life are so meager and so uncertain; and moreover, when we deal with information which even persons of our own generation withdraw from the attention of the observer. We know very little concerning Leonardo's youth. He was born in 1452 in the little city of Vinci between Florence and Empoli; he was an illegitimate child which was surely not considered a great popular stain in that time. His father was Ser Piero da Vinci, a notary and descendant of notaries and farmers, who took their name from the place Vinci; his mother, a certain Caterina, probably a peasant girl, who later married another native of Vinci. Nothing else about his mother appears in the life history of Leonardo, only the writer Merejkowski believed to have found some traces of her. The only definite information about Leonardo's childhood is furnished by a legal document from the year 1457, a register of assessment in which Vinci Leonardo is mentioned among the members of the family as a five-year-old illegitimate child of Ser Piero.[24] As the marriage of Ser Piero with Donna Albiera remained childless the little Leonardo could be brought up in his father's house. He did not leave this house until he entered as apprentice--it is not known what year--in the studio of Andrea del Verrocchio. In 1472 Leonardo's name could already be found in the register of the members of the "Compagnia dei Pittori." That is all. II As far as I know Leonardo only once interspersed in his scientific descriptions a communication from his childhood. In a passage where he speaks about the flight of the vulture, he suddenly interrupts himself in order to follow up a memory from very early years which came to his mind. "_It seems that it had been destined before that I should occupy myself so thoroughly with the vulture, for it comes to my mind as a very early memory, when I was still in the cradle, a vulture came down to me, he opened my mouth with his tail and struck me a few times with his tail against my lips._"[25]