On April 25, 1356, the Feast of St. Mark, a priest named Don Pietro celebrating Mass at the Augustinian church in Macerata had been troubled for some time by doubts about the Real Presence. At the moment of the fraction — when the priest breaks the consecrated host into pieces — blood spurted from the host and soaked through the corporal cloth, then through the altar cloth beneath it.
The bishop, alerted at once, brought the bloodied corporal to the Cathedral. Pope Innocent VI authorised public veneration. The relic, fitted into a precious crystal reliquary, has been venerated in Macerata Cathedral for nearly seven centuries. The bloodstains, examined repeatedly, remain visible.