The Piccolomini Library is a monumental room in the Siena cathedral. Located along the left aisle, before the transept, it was built in 1492 by the Archbishop of Siena, Cardinal Francesco Piccolomini Todeschini (later Pope Pius III) to house the very rich library heritage collected by his uncle Pope Pius II. Between 1502 and 1507 it was completely frescoed by Pinturicchio and assistants, including the Bolognese Amico Aspertini and the young Raffaello Sanzio.