This section is from the book "Leonardo Da Vinci: A Psychosexual Study Of An Infantile Reminiscence", by Sigmund Freud. Also available from Amazon: Leonardo da Vinci: A Psychosexual Study of an Infantile Reminiscence.
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 milture came down to me, he opened my mouth with his tail mid struck me a few times with his tail against my lips."
We have here an infantile memory and to be sure of die strangest sort. It is strange on account of its content and on account of the time of life in which it was fixed. That a person could retain a memory of die nursing period is perhaps not impossible, but it can in no way be taken as certain. But what diis memory of Leonardo states, namely, that a vulture opened the child's mouth widi its tail, sounds so improbable, so fabulous, diat anodier conception which puts an end to the two difficulties with one stroke appeals much more to our judgment. The scene of the vulture is not a memory of Leonardo, but a fantasy which he formed later, and transferred into his childhood. The childhood memories of persons often have no different origin. As a matter of fact, diey are not fixated from an experience like the conscious memories from the time of maturity and tiien repeated, but are not produced until a later period when childhood is already past, they are dien changed and disguised and put in die service of later tendencies, so that in general they cannot be strictly differentiated from fantasies. Their nature will perhaps be best understood by recalling the manner in which history writing originated among ancient nations. As long as the nation was small and weak it gave no thought to the writing of its history. It tilled die soil of its land, defended its existence against its neighbors by seeking to wrest land from diem and endeavored to become rich. It was a heroic but unhistoric time. Then came another age, a period of self-realization in which the nation felt rich and powerful, and it was dien that it experienced the need to discover its origin and how it developed. The history-writing which then continued to register present events also direw its backward glance at die past, gathered traditions and legends, interpreted what survived from olden times into customs and uses, and thus created a history of past ages. It is quite natural diat diis history of the past ages is more the expression of opinions and desires of the present than a faithful picture of die past, for many a tiling escaped the people's memory, other things became distorted, some trace of the past was misunderstood and interpreted in the sense of the present; and besides one does not write history from motives of objective curiosity, but because one desires to impress one's contemporaries, to stimulate and extol them, or to hold the mirror up to diem. The conscious memory of a person concerning die experiences of his maturity may now be fully compared to diat of history writing, and his infantile memories, as far as dieir origin and reliability are concerned will actually correspond to the history of the primitive period of a people which was compiled later with purposive intent.
Now one may think that if Leonardo's story of the vulture which visited him in his cradle is only a fantasy of later birth, it is hardly wordi while giving more time to it. One could easily explain it by his openly avowed inclination to occupy himself with the problem of the flight of the bird which would lend to this fantasy an air of predetermined fate. But with this depreciation commits as great an injustice as simply ignoring the material of legends, traditions, and interpretations in the primitive history of a people. Notwithstanding all distortions and misunderstandings to die contrary diey still represent the reality of the past; they represent what die people formed out of die experiences of its past age under the domination of once powerful and still effective motives, and if diese distortions could be unraveled through the knowledge of all effective forces, one would surely discover the historic truth under this legendary material. The same holds true for the infantile reminiscences or for the fantasies of individuals. What a person thinks he recalls from his childhood is not of an indifferent nature. As a rule die memory remnants, which he himself does not understand, conceal invaluable evidences of die most important features of his psychic development. As the psychoanalytic technique affords us excellent means for bringing to light this concealed material, we shall venture the attempt to fill the gaps in the history of Leonardo's life dirough die analysis of his infantile fantasy. And if we should not attain a satisfactory degree of certainty, we will have to console ourselves with the fact that so many other investigations about this great and mysterious man have met no better fate.
When we examine Leonardo's vulture-fantasy widi die eyes of a psychoanalyst, it does not seem strange very long; we recall diat we have often found similar structures in dreams, so diat we may venture to translate this fantasy from its strange language into words diat are universally understood. The translation then follows an erotic direction. Tail, "coda," is one of the most familiar symbols, as well as a substitutive designation, of the male member which is no less true in Italian than in other languages. The situation contained in the fantasy, that a vulture opened the moutii of the child and forcefully belabored it with its tail, corresponds to die idea of fellatio, a sexual act in which the member is placed into the mouth of the other person. Strangely enough this fantasy is altogether of a passive character; it resembles certain dreams and fantasies of women and of passive homosexuals who play die feminine part in sexual rerations.