Cascia in Umbria, known to everyone as the city of St. Rita, is also the place in which the Relic of an extraordinary eucharistic miracle that occurred in Siena in 1330 is preserved.

In the environs of Siena, a priest, on being requested to administer the holy sacraments to an ailing peasant, took a consecrated Host, placed it irreverently between the pages of his breviary which he tucked under his arm, and went to the home of the sick man. After hearing his Confession, the priest opened the book to take out the consecrated Host, but greatly to his astonishment, saw that it had turned red with fresh blood, so much so as to have impregnated both of the pages between which it had been placed. The priest, confused and penitent, went to Siena, to the Augustinian monastery, to describe what had happened to Father Simone Fidati of Cascia, a renowned preacher and religious of holy life. The latter, on hearing the priest's story and seeing with his own eyes the miraculous sign, granted him pardon, and asked him for permission to keep the two pages of the breviary stained with blood. One of them he later took to Perugia, and the other - the one to which the consecrated Host adhered - to Cascia, to the church of Sant'Agostino.

Over the centuries, this illustrious Relic has always been honoured by the faithful with, great veneration, and the Supreme Pontiffs have promoted its cult with many special indulgences, including that of the Portiuncula granted by Pope Boniface IX in 1401.

The miraculous event is particularly commemorated each year by the feast of Corpus Christi, when the Relic is borne solemnly in procession.

In 1930, on the occasion of the sixth centenary of the event, a Eucharistic Congress for the entire diocese of Norcia was held in Cascia; it was then that a precious and artistic Monstrance for displaying the Relic was inaugurated, and all the available historical documentation regarding it published.

A mention of one singular phenomenon associated with the Relic should not be omitted: many people have noted in those blood stains almost the expression of a suffering human face, and this has also been ascertained by photographic reproduction.