Mass of Saint Gregory

The Mass of Saint Gregory is a subject in Roman Catholic art which first appears in the late Middle Ages and was still found in the Counter-Reformation. Pope Gregory I (c. 540–604) is shown saying Mass just as a vision of Christ as the Man of Sorrows has appeared on the altar in front of him, in response to the Pope's prayers for a sign to convince a doubter of the doctrine of transubstantiation.

The earliest version of the story is found in the 8th-century biography of Gregory by Paul the Deacon, and was repeated in the 9th-century one by John the Deacon. In this version, the Pope was saying Mass when a woman present started to laugh at the time of the Communion, saying to a companion that she could not believe the bread was Christ, as she herself had baked it. Gregory prayed for a sign, and the host turned into a bleeding finger.

In the popular 13th century compilation the Golden Legend this story is retained, but other versions conflate the legend with other stories and the finger is changed into a visionary appearance of the whole of Christ on the altar, and the doubter becomes one of the deacons.

The story was hardly seen in art until the Jubilee Year of 1350, when pilgrims to Rome saw a Byzantine icon, the Imago Pietatis, in the basilica of Santa Croce in Gerusalemme, which was claimed to have been made at the time of the vision as a true representation. In this the figure of Christ was typical of the Byzantine forerunners of the Man of Sorrows, at half-length, with crossed hands and a head slumped sideways to the viewer's left. According to Gertrud Schiller and the German scholars she cites, this has now been lost, but is known from many copies, including the small Byzantine micromosaic icon of about 1300 now in Santa Croce. This image seems to have had, perhaps initially only for the Jubilee, a Papal indulgence of 14,000 years granted for prayers said in its presence. This form of the image, converted to a more standard Western Man of Sorrows, rising from the tabernacle on the altar, shown as a tomb-like box, with the Arma Christi around him, became standard across Europe, and very popular, especially north of the Alps, as an altarpiece, in miniatures in illuminated manuscripts, and other media. The strong connection of the image with indulgences was also maintained, and largely escaped from any Papal control. There was another Jubilee year in 1500, and the years on either side of this perhaps show the height of popularity of the image. It often appeared in books of hours, usually at the start of the Hours of the Cross or Penitential Psalms.

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