Sketched beside some of the machines on the ragged but important Uffizi sheet of 1478 is another kind of counterbalance, a contrast between two typologies that would become a fixation for Leonardo: the wizened, contemplative face of an old man and the fresh, inquisitive visage of a youth – an embodiment of Aristotle's decree that “each thing may be better known through its opposite” (fig. 32). Eventually, as we shall see, this juxtaposition would carry religious and spiritual connotations in certain of Leonardo's works, notably his representations of the Adoration of the Magi and Last Supper. However, we might rather assume that, at this relatively early stage of his career, his musings had something to do with his family situation. The grandfather, Antonio, would have been a constant, possibly doting, presence in the young Leonardo's life until the old man passed away in 1464 at age 92. With a father who was mainly absent, engaged in business in Florence, an estranged mother (who had moved with her husband to another village), and a stepmother who died prematurely, Leonardo likely felt a special closeness to his grandparents, with whom he lived for nearly a dozen years. In the countless drawings of the aged that he made over the course of his career, one often senses a certain reverence and intimacy.