Between 1492 and 1502, Cardinal Francesco, Bishop of Siena and future Pope Pius III had a room designed, built in several lateral rooms on the left side of the Cathedral of Santa Maria Assunta, to accommodate the precious book collections that belonged to his uncle, the great and learned Pius II, Enea Silvio Piccolomini, the man who had built man's ideal city in Pienza. After his death in 1464, his precious manuscripts and his life needed to find a precious place in which to be kept. The pictorial decoration was entrusted to Pinturicchio, for whom a contract containing all the requests that needed to be satisfied was stipulated. Evidence of this is in Vasari's "Vite" (Lives), where we can read that the walls were to contain ten stories from the life of Pius II, and Pinturicchio was "tenuto a fare tutti li disegni delle istorie di sua mano in cartoni et in muro, fare le teste di sua mano tutte in fresco, et in secho ritocchare et finire infino a la perfectione sua” (required to do all the drawings of the stories himself on cardboard and on the wall, paint the heads himself in fresh paint and, when dry, adjust and finish them to perfection). The construction of the Library represented an unusual iconographic programme for the sixteenth century: on the one hand it enhanced the legitimacy of the papal power, which had been violently questioned not long before by Savonarola, while on the other hand, it glorified the Piccolomini family and, above all, the enlightenment of Pius II's Humanism. The Stories of Pius II were the apotheosis of fifteenth-century narrative style in its most elegant version, filled with Flemish charm. The effect is that of rational order, made up of certainties, that reflected the thinking of the great Enea Silvio Piccolomini. Unfortunately, the sudden death of Pius III on 18 October 1503 inevitably cause the performance of the works to come to a halt, also because, in the meantime, the painter was commissioned by the late pontiff's brother, Andrea di Nanni Piccolomini to carry out another job: a large commemorative fresco dedicated to the coronation of Pius III, to be created above the entrance to the Library, along the wall of the left nave. It was completed on 19 February, 1504. Inside the Library, you can admire the group of the Three Graces, located in the centre of the room, a Roman copy of a Hellenistic original from the 2nd or 3rd century BC, purchased by Cardinal Francesco, while along the walls there are wooden showcases containing the Chorales of the Cathedral's sacristy. Next is the episode of Enea Silvio, ambassador to the court of Scotland, with the protagonist depicted while delivering a speech to the King to convince him to join forces with Charles VII, king of France, against the English. Behind the main scene, beyond an ancient decorated loggia, there is a magnificent landscape of Nordic charm, dotted with castles and towers and crossed by a river that flows into the sea. Then there is the poetic coronation with a laurel crown by Emperor Frederick III, to whom Enea Silvio Piccolomini was secretary.