Mahtan is the father of Nerdanel, wife of Fëanor, in The Silmarillion. Although his mentions in the text are few, Mahtan does much to shape the course of events in the book, and Tolkien's depiction of his character provides valuable insights into the theme of the abuse and corruption of knowledge that pervades Tolkien's books.
Much of what we know about Mahtan comes from sources outside the published Silmarillion. Within The Silmarillion, he is defined primarily by his relationship to his daughter Nerdanel and, through her, his resulting influence on Fëanor. When we meet Mahtan for the first time, he is presented using both this influence and his loyalty to Aulë, the great smith of the Valar:
While still in his early youth [Fëanor] wedded Nerdanel, the daughter of a great smith named Mahtan, among those of the Noldor most dear to Aulë; and of Mahtan he learned much of the making of things in metal and in stone.1
This presents an intriguing duality. Mahtan's influence over Fëanor entangle him firmly in Fëanor's later grievous deeds. While Fëanor is credited with the invention of the gemcraft that would lead to the creation of the Silmarils2--a mixed blessing, at best--Mahtan's instruction is credited with providing Fëanor with the knowledge he used to craft swords and other weapons of war, thus introducing violence to the Elves of Aman:
And Fëanor made a secret forge, of which not even Melkor was aware; and there he tempered fell swords for himself and for his sons, and made tall helms with plumes of red. Bitterly did Mahtan rue the day when he taught to the husband of Nerdanel all the lore of metalwork that he had learned of Aulë.3
In the published texts, these two passages are the only mention of Mahtan's name, making his legacy his instruction of Fëanor in crafts that were later used to make weapons and armor. That the emphasis is placed here--and that Mahtan so explicitly grieves his decision to do what must have seem innocuous and likely not even noteworthy at the time--will be discussed in the next section, as it relates to Tolkien's ideas about the misuse and corruption of knowledge.
Mahtan is treated more fully and, in places, in a slightly but significantly different manner in earlier drafts of The Silmarillion. Mahtan first appears in a draft that Christopher Tolkien identifies as The Later Quenta Silmarillion (2), or LQ2, which was produced as a typed copy around 1958 in what Christopher Tolkien identifies as "a second phase in his [JJRT's] later work on The Silmarillion," embarked upon after the publication of The Lord of the Rings freed him to again concentrate on the earlier as-yet-unpublished myths.4 As in the published text, Mahtan is introduced through his relationship to Nerdanel and, therefore, Fëanor, as part of an expanded passage that describes Nerdanel more fully and presents Mahtan's role as slightly but significantly different as in the published Silmarillion:
While still in early youth Feanor wedded Nerdanel, a maiden of the Noldor; at which many wondered, for she was not among the fairest of her people. But she was strong, and free of mind, and filled with the desire of knowledge. In her youth she loved to wander far from the dwellings of the Noldor, either beside the long shores of the Sea or in the hills; and thus she and Feanor had met and were companions in many journeys. Her father, Mahtan, was a great smith, and among those of the Noldor most dear to the heart of Aule. Of Mahtan Nerdanel learned much of crafts that women of the Noldor seldom used: the making of things of metal and stone. She made images, some of the Valar in their forms visible, and many others of men and women of the Eldar, and these were so like that their friends, if they knew not her art, would speak to them; but many things she wrought also of her own thought in shapes strong and strange but beautiful. (Emphasis mine)5
According to Christopher Tolkien's notes, a later typescript made based on this chapter eliminates the passage above.6 Christopher does not provide the second text, and this is the final draft we see of the "Of Fëanor" chapter. Christopher doesn't say whether the later typescript included anything about Mahtan; certainly it suggests that the entire passage was missing, presumably leaving Christopher with the editorial decision to reintroduce it. However, as is evident by the emphasized text, he also altered it. Mahtan did not teach his skills to Fëanor; he taught them to Nerdanel. Later, LQ2 contains the passage about Mahtan "ruing the day" he taught metalsmithing to Fëanor, so the idea that Mahtan passed along this knowledge to his son-in-law was clearly present at this stage as well.7 Why the change? Why would Christopher not only significantly cut but also rewrite the passage about Nerdanel and Mahtan? In Arda Reconstructed, Douglas Charles Kane hypothesizes that Christopher's edits might have aimed to establish consistency between the two passages about Mahtan, acknowledging also,
However, I think it is an important detail that he taught these crafts to Nerdanel as well, and that it is unfortunate that Christopher changed the clear meaning of this passage. This is one of the most blatant examples of how Christopher's changes appear to weaken an important female character.8
From the perspective of studying Mahtan's character, the original passage establishes a relationship between Nerdanel and her father that is missing from the published text. It also, importantly, suggests that at least some of Fëanor's knowledge and skill with metal and stone craft comes from Nerdanel rather than directly from Mahtan. This alters the theme of the use, abuse, and corruption of knowledge in an important way, as will be discussed below.
The essay The Shibboleth of Fëanor (written in 1968 at the earliest) offers additional details about Mahtan's character, in particular his loyalty to Aulë. In a note about Maedhros's name, Mahtan's "red-brown hair"--a distinctive trait and a fan favorite when writing his character--is first established:
But [Maedhros], and the youngest, inherited the rare red-brown hair of Nerdanel's kin. Her father had the epessë [nickname] of rusco 'fox'.9
Later, as an endnote to the essay, Christopher Tolkien includes an additional page's worth of material that was separately typed at the same time as the passage quoted above:
Nerdanel's father was an 'Aulendil' [> 'Aulendur'], and became a great smith. He loved copper, and set it above gold.
His name was [space; pencilled later Sarmo?], but he was most widely known as Urundil 'copper-lover'. He usually wore a band of copper about his head. His hair was not as dark or black as was that of most of the Ñoldor, but brown, and had glints of coppery-red in it. Of Nerdanel's seven children the oldest, and the twins (a very rare thing among the Eldar) had hair of this kind. The eldest also wore a copper circlet.
A note is appended to Aulendur:
'Servant of Aulë': sc. one who was devoted to that Vala. It was applied especially to those persons, or families, among the Ñoldor who actually entered Aulë's service, and who in return received instruction from him.
A second note on this page comments on the name Urundil:
√RUN 'red, glowing', most often applied to things like embers, hence adjective runya, Sindarin ruin ' "fiery" red'. The Eldar had words for some metals, because under Oromë's instruction they had devised weapons against Morgoth's servants especially on the March, but the only ones that appear in all Eldarin languages were iron, copper, gold and silver (ANGA, URUN> MALAT> KYELEP).
Earlier Nerdanel's father, the great smith, had been named Mahtan (see X.272, 277), and he was so called in the published Silmarillion. For earlier statements concerning the arming of the Eldar on the Great Journey see X.276-7, 281.]10
The passage above provides the bulk of what we know about Mahtan, from the frivolous, such as his preference of copper to gold, to the important connections to Nerdanel's family that arise and, most importantly, his identification as one of the Aulendur. These details are only hinted at in the published work.
Mahtan's deep connection to Aulë puts him in league with some interesting company. Aulë's students have a bad tendency to become corrupted, obsessed with power and control: Sauron, Saruman, and of course, Fëanor are all associated at various points in the story with Aulë and all fall spectacularly into corruption. This seems to eclipse mere coincidence into significance: What, exactly, about the Vala of smithcraft encourages bad behavior? Aulë himself seems a warm, empathetic, and helpful character. Presumably, then, it is not mere contact with Aulë that corrupts--as, for example, extended contact with Melkor might be assumed to do--but the nature of those attracted to Aulë that puts them in danger of corruption.
Tolkien seemed to distrust deeply the motives of creators--the Aulës and Fëanors of his invented universe--and what they would use their skills for. Those who are masters of technological skill seem unable to confine their work to what Tolkien considered appropriate: Fëanor made the Silmarils and weapons, Celebrimbor made the Rings of Power, Sauron made the One Ring, Saruman made the machines of Isengard. Oftentimes, these inventions defy the natural order, allowing the consolidation of power and the domination of the wills of others, in addition to destroying the pastoral landscapes that Tolkien loved. Of course, Tolkien was himself a man of knowledge and invention; how did he reconcile his own skills with the grim fate he assigned to the creators in his fictional world? In The Shibboleth of Fëanor, he distinguishes between the different types of knowledge: nolmë he describes as knowledge in philosophy and the theoretical sciences, including linguistics; kurwë he describes as "technical skill and invention." He is careful to note that Fëanor, while the greatest of the Noldor in kurwë, is not the greatest in nolmë.11 In short, Sauron, Saruman, and Fëanor--and Mahtan--and their knowledge are of a different kind than himself.
Mahtan does not fall as the others do. Yet, he is explicitly connected with the fall of Fëanor and the Noldor, and Tolkien is careful to note that the seemingly innocent Mahtan was the one who taught Fëanor all he needed to know to slaughter his kin at Alqualondë and spread war and bloodshed across the sea to Middle-earth. The very fact that Tolkien gave Mahtan a reaction of guilt to this is telling. Knowledge is generally regarded as neutral, with the responsibility for its use for good or evil ultimately resting with the practitioner, not the teacher. For example, a physician skilled in toxicology can use that skill to save the lives of patients who have ingested poisons, or can use that skill to manufacture poisons able to take a life with a low risk of detection. In the latter instance, no one would think to blame the practitioner's instructors in medical school, and these individuals likely wouldn't lose much sleep either, feeling that they should have somehow known to withhold that knowledge from the eventual poisoner. The very notion seems ridiculous. Yet, it is easier to imagine a person skilled in, say, bomb-making teaching that skill to someone who later uses it to take lives and feeling guilty about that. It is a skill inclined toward violence and havoc, and the very act of wanting to learn it suggests potential depravity in the student. So it goes with Mahtan: In Tolkien's world, where kurwë is a slippery slope to corruption and violence, Mahtan should have been more careful in widely sharing that knowledge or, at the least, should have recognized that Fëanor, simply for wanting to know it, was inclined toward corruption.
In this sense, the change in the text to make Fëanor, not Nerdanel, Mahtan's student makes sense. Nerdanel never becomes corrupted; in fact, she is one of the Noldor who stands firmest as Fëanor begins his slide into ruin. She leaves him early and refuses to be cajoled, even with her children used as a reward, into forsaking her sense of rightness. If Aulë's knowledge passes to Mahtan and then to Nerdanel, both of whom remain upright and uncorrupted, it suggests that that knowledge is not particularly perilous. By giving it to Fëanor instead, the perils of kurwë are again underscored.
So what saves Mahtan? Aside from his implication as Fëanor's teacher in the fall of the Noldor, Mahtan does not become corrupted. He is not even mentioned in conjunction with the rebellion of the Noldor. He remains loyal to the Valar, in particular to Aulë. Nerdanel shares this with him, a fact that prickles Fëanor when he accuses her of losing her children because she was "cozened by Aulë."12 He sees an unbridgeable gap between her objectives and his. Mahtan and Nerdanel, in other words, know their place; they do not, through their skill in forcing unyielding substances to obey their wills, gain any delusions of grandeur. They do not aspire to wield power in excess of what is appropriate for people of their station in life.