The Diocesan Museum of Pienza is located in the Episcopal Palace, or Palazzo Borgia, within the architectural complex of the Piazza and Cathedral. Together these buildings make up the monumental centre of the town-wide renovation project commissioned by the humanist Pope Pius II Piccolomini and designed by Bernardo Rossellino.
The museum evolved from the treasure-filled Museum of the Cathderal and came to include numerous works from various churches in the surrounding territory. It is laid out in 11 rooms that gather together art from Pienza and from other towns nearby.
The collection boasts masterpieces of 14th-century Sienese painting, such as the famous Madonna of Monticchiello by Pietro Lorenzetti, and the large panel with the Madonna della Misericordia (Madonna of Mercy) by Bartolo di Fredi, originally housed in the Baptistry of Pienza.
The Sienese School of the 1400s is also amply represented by works of the highest quality, including Il Vecchietta’s Madonna on a Throne between St. Blaise, St. John the Baptist, St. Nicholas and St. Florian, a painting that shows the influence of Florentine innovations in terms of its clear, sharp brightness and of its use of perspective.
No less magnificent are the 16th-century Madonna of Mercy by Luca Signorelli and the Renaissance sculptures by Domenico di Niccolò dei Cori. Later pieces by the Sienese School are those of Vincenzo Rustici, Francesco Rustici, Bernardino Mei and Giuseppe Nicola Nasini.
The museum contains an outstanding collection of goldwork from the 13th to the 19th century. The liturgical furnishings donated to the Cathedral by Pius II are of special importance.
Perhaps the most highly prized piece is the Cope of Pius II. The despot Tommaso Paleologo donated this ecclesiastical vestment to the Pope, who in turn gave it to the Cathedral. The English-made cope is decorated with twenty-seven stories from the life of the Virgin, and it demonstrates the enlightened personality of Pius II, undisputedly the most prominent figure in the history of Pienza.