On February 23, 1239, the Aragonese Christian army of King Jaime I — having stopped to celebrate Mass on a hillside near Luchente in Valencia during the Reconquista — was about to receive Communion when scouts brought news of a sudden Moorish attack. The celebrant, Father Mateo Martínez, wrapped the six consecrated hosts in the corporal and hid them under a stone before joining the battle.
The Christians won. Returning to recover the hosts, they found the corporal stained — each of the six hosts had impressed a perfect bloody print on the linen. The bishop, alerted at once, ordered the relic taken to a major city. To determine which, the corporal was placed in a casket on the back of a mule that was left untethered. The mule walked the corporal across Aragon for thirteen days, refusing food, water, and rest at every town until it dropped dead at the gates of Daroca on March 7, 1239.
The corporal has been preserved there ever since, in a silver-gilt reliquary in the Colegiata of Santa María de los Corporales. It is processed each year on Corpus Christi and on the Sunday after Easter. The original six bloodstains are still visible in the linen. Pope John XXII confirmed the cult in 1325.