The glittering vault decorated in the "grotesque" style contains a series of allegorical figures, pastoral scenes, bacchanalia and marine thiasoi, two larger panels depict episodes from classical mythology (Diana and Endymion and the Rape of Proserpina) and the arms of Cardinal Todeschini Piccolomini – five crescents beneath a cardinal's hat – loom large in the centre of the ceiling.
The frescoes showing Scenes from the Life of Aeneas Silvius Piccolomini unfurl on three of the Library's four walls, the fourth wall consisting in windows. The "painted biography" method comprises scenes focusing on a single individual whose life is outlined in a series of salient episodes and events shown in strict chronological order. Thus the north-eastern wall of the Library has four scenes basically recounting Aeneas Silvius' youth (the young man is portrayed with flowing blond locks) from his departure for the Council of Basle to the scene in which he is reconciled with Pope Eugene IV and subsequently ordained bishop. The two panels on the south-eastern wall show Aeneas Silvius exercising his functions as a bishop and being made a cardinal. And the four scenes of the south-western wall depict episodes from his life as pope, stretching from his coronation to his Arrival in Ancona where he surrendered his soul to God.
The Life of Pius II written by the humanist Giovanni Antonio Campano, who was secretary both to Aeneas Silvius and subsequently to his nephew Francesco Todeschini, and Pius II's own Commentarii are crucial reference works for the origin of the individual scenes and for gaining a fuller picture of Aeneas Silvius' life.
The fifth scene in the cycle depicta one of the better-known episodes, showing the meeting (in which the pope played a facilitator's role) between the Emperor Frederick III and Eleonora of Aragon that took place by the city's Porta Camollia gate on 24 February 1452. Pinturicchio dwells at length on the depiction of the fabrics, adornments and jewels worn by the figures gathered around the august bride- and bridegroom-to-be.