In the 13th century, a Portuguese woman who’d been demonically oppressed resolved to do the unthinkable by taking her own life by drowning herself in the Tagus River. On her way to the river, she passed a shrine erected in honor of the great orator and miracle-worker, St. Anthony of Padua. She stopped to pray, one last time. As she prayed, she saw St. Anthony standing before her, saying, «‘Arise woman, and take this paper, which will free you from the molestations of the Evil One.» Then he gave her a parchment inscribed with what is now known as the «Brief (i.e., «Letter») of St. Anthony,» 1 and she was now free from demonic oppression and the desire to do away with herself.

News of this miracle spread, even to the King who asked the woman for the Brief. He placed it with the Crown Jewels of Portugal, which was fine for the King, but bad for the woman. After the Brief was no longer with her, she began to weaken and lapse, so the King made a copy for her that restored her to her healed state. Other copies of the Brief were spread to help the faithful fight the Evil One and remind them that Christ has conquered.

The Brief consists of a depiction of a Cross, and words which, forming a rhyme in the Latin, hearken back to Apocalypse 5:5, «And one of the ancients said to me: Weep not: Behold the Lion of the Tribe of Juda, the Root of David, hath prevailed to open the Book and to loose the Seven Seals thereof.»