No. 1: Enea Piccolomini Leaves for the Council of Basel (detail)

In contrast to Perugino, the mature Pinturicchio seems to have gained artistic strength rather than losing it, and his frescoes in the grandiose Piccolomini Library in Siena are masterpieces in his personal style. The narratives deal with the life of the Piccolomini family's first pope, Pius II. Here the future Pope, Aeneas Silvius, is shown as a young man setting out for Basel. The preparatory drawing is often regarded as by Raphael, indicating the possibility of a rather remarkable collaboration.

In the fresco the elegant manner of Pinturicchio's style is especially discernible in the central figure, that of the youthful Aeneas Silvius, heroically set upon a white horse placed obliquely in space. The lad turns sharply to face the spectator. His refined features and modish garments and the delicate hound, highbred and quivering, reflect a set of choices that can be traced back to artists like Pisanello and Sassetta in the previous generation. Seen through a high arch with decorative devices carried down from the folly articulated ceiling which Pinturicchio must have worked on first, the landscape takes up more than half the available space.

A special bonus is included, a tour de force and one not provided in the drawing: a storm at sea and a rainbow in the sky. These daring naturalistic inclusions are examples of the originality that crops up in this cycle. Significant stylistic breaks with his earlier works, however, do not occur.