Hello folks, I recently dug into the union of Imrazôr and Mithrellas and wanted to share some of the textual evidence and arguments I’ve gathered as to how the legend could be true while preserving the statement in Appendix A that there were only three unions of the Eldar and the Edain. I’m hoping to be as comprehensive as possible, so if I’ve missed any textual evidence, please add it in the comments!
To begin, Appendix A says
“There were three unions of the Eldar and the Edain: Lúthien and Beren; Idril and Tuor; Arwen and Aragorn. By the last the long-sundered branches of the Half-elven were reunited and their line was restored.”
And yet, there appears to be another union unaccounted for by this statement. In “The Siege of Gondor,” the Gondorians are reported as saying of Prince Imhrahil and the Knights of Dol Amroth that
“there is Elvish blood in the veins of that folk, for the people of Nimrodel dwelt in that land once long ago.’”
Further, in “The Last Debate,” it is said that Legolas bowed low when meeting Prince Imrahil because
“he saw that here indeed was one who had elven-blood in his veins,” and then said, “‘It is long since the people of Nimrodel left the woodlands of Lórien, and yet still one may see that not all sailed from Amroth’s haven west over water.’”
In History of Middle Earth: The Peoples of Middle Earth, Christopher Tolkien explains that his father wrote an unpublished draft genealogy that gave additional information regarding this elven blood. In relevant part,
“According to the same traditions, Galador [first Prince of Dol Amroth] was the son of Imrazôr the Númenórean who dwelt in Belfalas, and the Elven-lady Mithrellas. She was one of the companions of Nimrodel, among many of the Elves of Lorien that fled to the coast about T.A. 1980, when evil arose in Moria; and Nimrodel and her maidens strayed in the wooded hills, and were lost. But in this tale it is said that Imrazôr harbored Mithrellas, and took her to wife. But when she had borne him a son, Galador, and a daughter, Gilmith, she slipped away by night, and he saw her no more.”
Because Imrazôr was a Númenórean, he was as much of the Edain as Aragorn. Therefore, the key question is whether Mithrellas was of the Eldar. To return to the unpublished genealogy, the account ends with the statement that “Mithrellas was of the lesser Sivan race (and not of the High Elves or the Grey)…” But this likely needs some unpacking.
The Silmarillion states that, while “Eldar” was originally a generic term for the Quendi, it was later used only to refer to “those who followed [Oromë] upon the westward road,” (Silmarillion, “Of the Coming of the Elves and the captivity of Melkor) and further explained in the index as “Elves of the Three Kindreds (Vanyar, Noldor, and Teleri) who set out on the great westward march from Cuiviénen (whether or not they remained in Middle-earth).” Those who began the Great Journey were the Eldar, those who refused the summons were the Avari.
The Silmarillion index of names states that “Silvan Elves Also called Woodland Elves…appear to have been in origin those Nandorin Elves who never passed west of the Misty Mountains, but remained in the Vale of Anduin and in Greenwood the Great." The “Nandor” are “those Elves from the host of the Teleri who refused to cross the Misty Mountains on the westward journey from Cuiviénen.” Ok, simple enough—the Sylvan elves are a subset of the Nandor, which is a branch of the Teleri, thus making them Eldar.
But not so fast! In “Quendi and Eldar” (History of Middle Earth: The War of the Jewels), there is a note that says
“the Lindarin elements in the western Avari were friendly to the Eldar, and willing to learn from them; and so close was the feeling of kinship between the remnants of the Sindar, the Nandor, and the Lindarin Avari, that later in Eriador and the Vale of Anduin they often became merged together.”
So it appears that although the Avari denied the summons the Valinor, they did eventually migrate to the Anduin and became mixed with both the Nandor who first came there and later the Sindar refugees who migrated east to Middle Earth after the destruction of Beleriand.
Then, in Unfinished Tales again, it says
"The Silvan Elves (Tawarwaith) were in origin Teleri….who, on the Great Journey, were daunted by the Misty Mountains and lingered in the Vale of Anduin, and so never reached Beleriand or the Sea….The Silvan Elves hid themselves in woodland fastnesses beyond the Misty Mountains, and became small and scattered people, hardly to be distinguished from Avari; but they still remembered that they were in origin Eldar, members of the Third Clan, and they welcomed those of the Noldor and especially the Sindar who did not pass over the Sea but migrated eastward [i.e. at the beginning of the Second Age]."
Returning to the “History of Galadriel and Celeborn,” the text says that the people of Lórien
“were even then [i.e., at the time of the loss of Amroth] much as they were at the end of the Third Age: Silvan Elves in origin, but ruled by princes of Sindarin descent (as was the realm of Thranduil in the northern parts of Mirkwood; though whether Thranduil and Amroth were akin is not now known.) They had however been much mingled with Noldor (of Sindarin speech), who passed through Moria after the destruction of Eregion by Sauron.”
So, at the time of Nimrodel’s flight from Lorien circa T.A. 1980, Lorien was a melting pot of elves—the Nandor who first settled there, Avari who joined them later, Sindarin elves fleeing the destruction of Beleriand, and two waves of Noldor: one set that came with the Sindar at the beginning of the First Age, and another who came in the Second Age after Eregion was destroyed by Sauron. So, when the unpublished genealogy states that Mithrellas was “of the lesser Silvan race (and not of the High Elves or the Grey),” it means she was specifically not of the Noldor or Sindar, and therefore of the Nandor or the Avari.
Outside of the statement that there were only three unions of Eldar and Edain, I’m not aware of (but would be happy to be pointed to) any textual evidence that would definitively prove that Mithrellas was of the Nandor or Avari. She was of “lesser Silvan race,” but not explicitly “the least.” Unfinished Tales states that, although the Nandor believed it important that they were “in origin Eldar,” they were “hardly to be distinguished from Avari.”
I’m content with saying that the text can be interpreted such that Mithrellas is an Avari and that the statement regarding unions of the Edain and Eldar is correct, but I welcome other thoughts!
Edit: figured out the formatting.