Happily the study of the intellectual side of human nature began, not with the search after a theoretical psychology - for that, Aristotle still sufficed - but with the endeavor to observe and to describe. The indispensable ballast of theory was limited to the popular doctrine of the four temperaments, in its then habitual union with the belief in the influence of the planets. Such conceptions may remain ineradicable in the minds of individuals, without hindering the general progress of the age. It certainly makes on us a singular impression, when we meet them at a time when human nature in its deepest essence and in all its characteristic expressions was not only known by exact observation, but represented by an immortal poetry and art. It sounds almost ludicrous when an otherwise competent observer considers Clement VII to be of a melancholy temperament, but defers his judgement to that of the physicians, who declare the Pope of a sanguine-choleric nature; or when we read that the same Gaston de Foix, the victor of Ravenna, whom Giorgione painted and Bambaia carved, and whom all the historians describe, had the saturnine temperament. No doubt those who use these expressions mean something by them; but the terms in which they tell us their meaning are strangely out of date in the Italy of the sixteenth century.
As examples of the free delineation of the human spirit, we shall first speak of the great poets of the fourteenth century.
