Cardinal and Archbishop of Siena Federico Todeschini founded the Libreria Piccolomini in 1502 in a large vaulted chamber accessed from the transept of the cathedral of Siena. The library was intended to serve as a repository for the large collection of manuscripts assembled by his uncle, the humanist scholar, diplomat and cardinal Enea Silvio Piccolomini, who served as Pope Pius II from 1458/64. Pius II made Todeschini a cardinal in 1460 at the age of 21. Throughout his career, Todeschini sought underscore his relationship to Pius II and the creation of the library restated that connection in the months leading up to his own accession to the papacy Pius III in 1503.
The aged Pius III died 26 days after his election. Nevertheless, the decoration of the library proceeded. The wall frescoes depicting episodes from the varied career of Pius II were painted between 1503/08 by Bernardino di Betto, or il Pinturicchio, who had recently finished painting the Borgia Apartments in the Apostolic Palace. According to Vasari, Pinturicchio invited the young Raphael, his fellow student in Perugino’s workshop) to contribute designs for several of the frescoes. Raphael’s drawings for the scenes depicting Enea Silvio Piccolomini departing for the Council of Basel and Piccolomini introducing Frederick III to Eleanora of Portugal survive and show that Pinturicchio faithfully executed his friend’s ideas). Raphael assisted in the painting of the frescoes as well and both artists included self-portraits in the cycle. Pinturicchio daringly gave his features to the foppishly-attired figure of Enea Silvio Piccolomini on horseback in the first scene; Raphael holds a candle at the canonization of Catherine of Siena.
Despite the completion of the frescoes in 1508, Pius II’s books were never transferred to the library. The choirbooks currently displayed on late-15th wooden shelves in the library space were commissioned by the cathedral chapter after the death of Pius II. They contain some of the finest examples of northern Italian book illumination by Liberale da Verona and Girolamo da Cremona, but have no connection to either Piccolomini pope.