It is located in the Stanza di Eliodoro, which is named after The Expulsion of Heliodorus from the Temple.

A Bohemian priest who doubted the doctrine of transubstantiation was celebrating mass at Bolsena, when the bread of the eucharist began to bleed.

The blood that spouted from the host fell onto the tablecloth in the shape of a cross and he was reconverted.

The following year, in 1264, Pope Urban IV instituted the Feast of Corpus Christi to celebrate this miraculous event.

Present in this painting is a self-portrait of the artist, Raphael, as one of the Swiss Guard in the lower right of the fresco, facing out with bound-up hair.