Between 1685 and 1687, the Opera della Metropolitana had the interior side of the central portal decorated, reusing for this purpose two monumental columns from the altar dedicated to the Four Crowned Saints. In order to reach the proper height, the columns had to be put on pedestals, around which were placed panels illustrating stories from the life of the Virgin Mary, carved by Urbano da Cortona for the destroyed chapel of Our Lady of Grace.
Five panels were inserted into the sides of these pedestals: two whole ones on the front sides, Our Lady Instructing the Apostles and Mary Bidding Farewell to the Apostles; for the smaller spaces on the shorter sides, three reliefs were chosen that lent themselves to adaptation. One illustrating the Birth of the Virgin was cut in two and the pieces attached to the exterior sides of the two pedestals, while the other two, which presented a central composition, that is, the Assumption of the Virgin and her Coronation, were cut down on both sides and set on the interior sides towards the portal.
Four sections found a new home in the railing above the portal: the Wedding of the Virgin, Mary’s Return to her Parents’ House, the Funeral of the Virgin, and her Burial.
Six more panels from the cycle were attached in the eighteenth century to the side of the bell tower inside the cathedral, under the Del Testa Piccolomini tomb. On the left of the door are shown The Transit of the Virgin, the Annunciation, and Joachim being Thrown Out of the Temple; on the right are Joachim among the Shepherds, Joachim’s Dream and the Meeting at the Golden Gate, and The Sacrifice of Joachim and Anne’s Dream. One last panel, the Announcement to Mary of her Death is now in the Museo dell’Opera.
All these reliefs decorated the pillars of the large arch that led into the chapel of Our Lady of Grace. This had been erected in 1448-1449, at the initiative of the communal government and with public financing, to honor more fittingly the venerated panel painting of Our Lady of Grace, now known as the Madonna of the Vow.
The Stories from the Life of the Virgin were carved by Urbano da Cortina between 1451 and 1459, but the decoration of the front of the chapel was graced by a work by Donatello, who moved to Siena in 1457 with the intention of living out his days there. He carved the large roundel of The Virgin and Child which for a long time decorated the side door of the cathedral (the original, now substituted in loco by a copy, is in the Museo dell’Opera), but was originally in the tympanum of this front.
The iconography of the scenes is borrowed from some examples of Sienese painting dedicated to the Virgin Mary: the stories on the crown of Duccio’s Maestà, which at the time still stood on the high altar, and the sequence of frescoes painted by Simone Martini and the Lorenzetti brothers on the façade of Santa Maria della Scala Hospital. Urbano da Cortona’s inspiration taken from the most illustrious models of Sienese painting bears witness to the great devotion centered on the chapel of Our Lady of Grace, the second Marian site in the cathedral after the high altar.