A lady (I think she was in Portugal, where St. Anthony was born, although Padua claims him now) was much troubled with evil spiritual forces that tormented her and kept her awake at night. Exhausted as she walked along the road, she fell asleep by a shrine to St. Anthony. The saint himself appeared to her in a dream or vision, and gave her a piece of paper which he told her to keep with her. When she woke, she found a piece of paper with these words written on it at her feet. She did as instructed and was no more troubled -- although some versions of the story say that her Bishop asked to borrow it, and her troubles started up again, so she went and got it back . . .