There was once the Pieve di Santo Stefano in the center of the Prato of the 900s, but between 1211 and 1457 a new building with Romanesque green-and-white striping rose on the site to become Prato's Duomo. The facade has a glazed terra-cotta Madonna and Sts. Stefano and Lorenzo (1489) by Andrea della Robbia above the main door. The beautiful Pulpit of the Sacred Girdle hangs off the facade's right corner, from which Prato's most revered relic, the Virgin Mary's girdle, is displayed five times yearly . The pulpit is a Michelozzo (design) and Donatello (sculpted friezes) collaborative effort (1434-38). The frolicking cherubs around the base are casts of Donatello's originals, now kept in the Museo dell'Opera.
Inside the church on the left is the Cappella della Cintola (Chapel of the Sacred Girdle), entirely frescoed (1392-95) by Agnolo Gaddi. On top of the altar stands one of Giovanni Pisano's finest sculptures, a small marble Madonna and Child (1317). Popping 2€ in the box buys you 5 minutes of light. The nave pulpit was carved by Mino da Fiesole and Antonio Rossellino (1469-73).
To access the church's prized, frescoed chapels, you have to pay a small fee. To the right of the high altar is the Cappella dell'Assunzione (Chapel of the Assumption), frescoed by Paolo Uccello and Andrea di Giusto with the Lives of St. Stephen and the Virgin (1436). St. Stephen was the first Christian martyr -- his death by stoning is the subject of the middle panel of the left-hand wall.
The frescoes (1452-66) covering the walls of the choir behind the high altar -- the Life of St. Stephen on the left wall (spot his martyrdom again to the left of the stained glass) and St. John the Baptist on the right -- comprise one of the masterpieces of Filippo Lippi, and indeed the early Renaissance. The amorous, monk-painter asked if a certain Lucrezia Buti, a beautiful young novice from the nearby convent, could model for his Madonnas. The nuns agreed, Filippo promptly seduced her, and the two ran off, eventually having a son, Filippino Lippi, who became an important painter in his own right. Supposedly Filippo did actually use Lucrezia in the paintings -- she's the graceful flowing figure of Salome dancing into the Feast of Herod on the right wall's lower register. Lippi portrayed himself, along with Fra' Diamante and the assistants who helped him here, on the left wall among the crowd mourning the passing of St. Stephen. (They're the little red-hatted group on the far right; Filippo is third in from the end.)