The crossing of boundaries is a fundamental aspect of The Lord of the Rings. The reader crosses into Faërie, the company crosses into Lórien, and Frodo and Sam cross into Mordor. The physical crossing is a crucial aspect of the story, but often, there is an aspect of worship that accompanies it. The singing or crying out about Elbereth, a name which can be seen as analogous to the Virgin Mary or another saint, often signals an important transition or revelation.
Catholicism is no stranger to the blending of the world with the immaterial as a result of worship or divine intervention: Moses received the ten commandments at Sinai, many Marian apparitions have been documented, and Tolkien discusses a vision he received in letter 89. In all of these cases, the fabric of the world seems to shift, where a portal is opened, blending the material and divine worlds. Tolkien describes how he seemed to perceive guardian angels being represented as individualized rays of light that extend into each person. This vision, like those of the mystics, seems to break the boundaries of the natural world and perceive something that exists beneath: the personalized connection of the angels and man.
The Lord of the Rings, while a “fundamentally religious and Catholic work,” does not explicitly define a religion that those of Middle-earth worship (Letter 142). However, there are many aspects that can be construed as religious; most clearly, the references to Elbereth Gilthoniel, which means Elbereth Starkindler. While it is not fully clear what she is, she seems to behave or be understood like a saint. As with crossing into Faërie and encountering the different life that exists there, their initiation and understanding of the fantastical world they live in begins with a song about Elbereth. Here, the reader and Frodo meet the Elves and the first concepts of religion. Frodo’s experience with the elves becomes mystical, seemingly like a “waking-dream” (I, ch. 3). This near-dreamlike state, which has many similarities to how mystics and possibly Tolkien describe divine visions, becomes the vector for Frodo to peer beyond the immediate world he knows and learn about what resides beyond the Shire: of elves, of things old and new, and of many more things. It is not a coincidence that the Elves, who are most commonly associated with Faërie, are the ones who start to bring him in, commencing with a song about Elbereth. However, it is also with the name of Elbereth that they say farewell before vanishing. The boundary of his known world begins to become fluid, letting that which he previously could not interact with permeate.
Accompanying the crying out of Elbereth as a battle cry at the Battle of Weathertop, another barrier is crossed. Frodo slips the ring on his finger, which changes the nature of his environment, where he becomes invisible to others, but the black riders become clearer and more defined. It is in this transitional state that Frodo invokes Elbereth’s name, as if invoking a saint, though the result is his swooning into unconsciousness and suffering a grave wound. It is in this moment that a great change occurs within Frodo. He literally becomes unconscious, signifying a gap, but he is struck with a great wound that must be healed. Not to mention the power of the ring is shown, where it, like the elves or mystic visions, can change the edges of the world and what permeates it.
The departure from Lórien is punctuated by Elbereth’s name, signifying the crossing of a threshold and the beginning of the rest of the journey. As they depart, they see the Lady Galadriel fade in the distance, being described as one would describe the Virgin Mary using aspects of the Litany of Loreto. The strong religious undertones emphasize the leaving of the mystical place of Lórien: a place that has strong connotations with paradise and similarities to the poem, “The Pearl.” Indeed, Elbereth’s name and the fading of Galadriel as a Madonna-like figure punctuate the ending of their time in a paradise-like land and the continued travel on their journey, except with the gifts they have now received. Thus, Elbereth does not only signify the beginning of a certain unveiling or part of their journey, but it also signifies the leaving of such mystical places. Seeming to correspond to how prayer brings them into the vision, but it is the ending of the prayer, which is signified by, in this case, a saint-like figure’s name, Elbereth, that pulls one out of the vision.
The song to Elbereth, at the close of the last chapter of The Return of the King, with the close of the Third Age, marks the departure of Frodo, Bilbo, and a great many elves. While it ends the time of many in Middle-earth, this sequence begins their journey aboard their ship westward. Here, it marks the ends of the novel, but in other ways, it marks the start. The appendices follow, and one can now behold “white shores and beyond them a far green country under a swift sunrise” (VI, ch. 9). In some ways, this parallels the beginning of the journey into Faërie, brought on by the elves with their song about Elbereth, except Frodo leaves with them. The parallel exists that it is through song and prayer that one becomes exposed to religion and the knowledge that comes with it, and at the end, while they may finish the story, the elves, like the story, exit with them, accompanying them beyond.
The religious aspect of Elbereth throughout The Lord of the Rings corresponds to the crossing of a threshold — the lifting of a veil or a major change in the adventure, whether at the beginning or the end. Religion functions similarly in the primary world. Tolkien perceived what he recorded as a vision that illuminates how he conceives of guardian angels connecting to every human being. In each of these instances, religion aids in the crossing of boundaries, changing what permeates into the world.
— ESW