It was customary in those times to have the Eucharistic bread prepared by the parishioners. Pope St. Gregory the Great was a direct eyewitness to this prodigy.
One Sunday, while celebrating the Sacred Mass in an ancient church dedicated to St. Peter, the Pope was distributing Communion and saw among the faithful in line, one of the women who had prepared the bread for the consecration and she was laughing out loud.
Troubled, the Pope cornered her and asked her to explain her behavior. She justified herself by saying that she could not believe that the bread she made with her very own hands could become the Body and Blood of Christ during the consecration.
St. Gregory denied her Communion and asked God to illuminate her. Having just finished praying, he saw that part of the bread prepared by the woman became Flesh and Blood.
The woman repented, knelt on the ground and began to cry. To this day, part of the relic of the miracle is housed in Anechs, Germany, near the local Benedictine monastery.