Today home to Siena's official archives, the Florentine-style Piccolomini Palace sits on the Piazza del Campo. It was commissioned by Cardinal Francesco Todeschini Piccolomini and built to a design by Bernardo Rossellino in 1459. At the time, Piccolomini was archbishop of Siena but later he was to become Pope Pius III. A building was needed to house the extensive book collection of Piccolomini's uncle, Pope Pius II.
Of the book collection, only a few choral tomes remain to be seen today. The main draw for visitors is the vividly colored frescoes that narrate the life of Pope Pius II. This ten-fresco cycle was painted by Bernardino di Betto (Pinturicchio) between the years 1503 and 1508.
The story starts with the pope's early days when in his job as an ecclesiastical secretary he traveled to Basle. The last fresco shows his death in Ancona while trying to put together a crusade against the Turkish infidels. Also to be seen in the Piccolomini Palace is a 3rd-century Roman copy of the Greek statue, The Three Graces.