He describes the spirit who visited him as dressed in "blue drapery, as the Madonna might in a picture by Raphael."
Interestingly, a year after Dickens wrote A Christmas Carol, the Protestant author had his own spiritual experience. He wrote about it in a letter to friend John Forster on September 30, 1844, while on a vacation in Genoa, Italy.
Let me tell you of a curious dream I had last Monday night; and of the fragments of reality I can collect, which helped to make it up. I have had a return of rheumatism in my back, and knotted round my waist like a girdle of pain; and had lain awake nearly all that night under the infliction, when I fell asleep and dreamed this dream.
In an indistinct place, which was quite sublime in its indistinctness, I was visited by a Spirit. I could not make out the face, nor do I recollect that I desired to do so. It wore a blue drapery, as the Madonna might in a picture by Raphael; and bore no resemblance to any one I have known except in stature. I think (but I am not sure) that I recognised the voice.
Anyway, I knew it was poor Mary’s spirit. I was not at all afraid, but in a great delight, so that I wept very much, and stretching out my arms to it called it “Dear.” At this, I thought it recoiled; and I felt immediately, that not being of my gross nature, I ought not to have addressed it so familiarly. “Forgive me!” I said. “We poor living creatures are only able to express ourselves by looks and words. I have used the word most natural to our affections; and you know my heart.” It was so full of compassion and sorrow for me — which I knew spiritually, for, as I have said, I didn’t perceive its emotions by its face — that it cut me to the heart; and I said, sobbing, “Oh! give me some token that you have really visited me!” “Form a wish,” it said.
I thought, reasoning with myself: “If I form a selfish wish it will vanish.” So I hastily discarded such hopes and anxieties of my own as came into my mind, and said, “Mrs. Hogarth is surrounded with great distresses” — observe, I never thought of saying “your mother” as to a mortal creature – “will you extricate her?” “Yes.” “And her extrication is to be a certainty to me, that this has really happened?” “Yes.” “But answer me one other question’” I said, in an agony of entreaty lest it should leave me. “What is the True religion?” As it paused a moment without replying, I said – Good God in such an agony of haste, lest it should go away ! – “You think, as I do, that the Form of religion does not so greatly matter, if we try to do good? or,” I said, observing that it still hesitated, and was moved with the greatest compassion for me, “perhaps the Roman Catholic is the best? perhaps it makes one think of God oftener, and believe in him more steadily?”
“For you,” said the Spirit, full of such heavenly tenderness for me, that I felt as if my heart would break; “for you, it is the best!” Then I awoke, with the tears running down my face, and myself in exactly the condition of the dream. It was just dawn. I called up Kate, and repeated it three or four times over, that I might not unconsciously make it plainer or stronger afterwards. It was exactly this.
Dickens wasn’t sure exactly the identity of the Spirit. He says that it “bore no resemblance to any one I have known except in stature,” but he refers to the spirit as “Mary’s spirit,” referring to his sister-in-law Mary Hogarth, who had passed away.
The Protestant author goes on in the letter to explain how he may have been influenced by his Italian room, full of Roman Catholic pieces of furniture, including an altar.
… there is a great altar in our bedroom, at which some family who once inhabited this palace had Mass performed in old time; and I had observed within myself, before going to bed, that there was a mark in the wall, above the sanctuary, where a religious picture used to be; and I had wondered within myself what the subject might have been, and what the face was like. Thirdly, I had been listening to the convent bells (which ring at intervals in the night), and so had thought, no doubt, of Roman Catholic services. And yet, for all this, put the case of that wish being fulfilled by any agency in which I had no hand; and I wonder whether I should regard it as a dream, or an actual Vision.
The validity of such a dream is difficult to evaluate from a single letter, but it would not have been the first time that the Virgin Mary visited a non-Catholic. She is even known to appear to atheists throughout history.
Dickens may have experienced a version of his own story, being visited by a heavenly woman who was trying to guide him to the practice of the Catholic religion.