A Sindarin name for Aulë. According to Christopher Tolkien, it appeared in a very late note, as a cognate of Q. Martamo (LT1A/Talka Marda). It is a combination of bâr “house, home, dwelling” and a mutated form -than of ✱tân “smith” (attested only in compounds).
Conceptual Development: The earliest form of this name was G. Martaglos “Smith of the World”, appearing in the Gnomish Lexicon from the 1910s (GL/18, LT1A/Talka Marda.026). A revised form ᴱN. Barthaglon “World Smith” appeared in Early Noldorin word lists from the 1920s (PE13/138). The name appeared as N. Barthan “Earth-smith” or “Earthbuilder” in The Etymologies from the 1930s, the source of the derivation given above (Ety/MBAR, TAN).
A title for Aulë appearing in a very late note (LT1A/Talka Marda). The second element is clearly tamo “smith”, and the first element “World” may be either mar(da) or már. I consider the first of these to be more likely: see the entry for mar(da) for discussion.
Conceptual Development: An early form of this name appeared in the Lost Tales: ᴱQ. Talka Marda “Smith of the World” (LT1/180, LT1A/Talka Marda). The name appeared in The Etymologies from the 1930s as ᴹQ. Martan(o) “Earth-smith”, a compound of mar “Earth” and tano “smith” (Ety/MBAR, TAN). In notes from the 1950s, Tolkien revised tano >> tamo (PE17/107), which is probably the origin of the later form of this name.