Tolkien's final First Age timeline

[Huinesoron]

Tolkien's last comment touching on the aging of the Eldar in Aman is from NoME 1.XVIII (1965): "Elvish ages must be counted in two different stages: growth-years (GY) and life-years (LY). The GYs were relatively swift and in Middle-earth = 3 loar. The LYs were very slow and in Middle-earth = 144 loar." The obvious implication here is that outside Middle-earth, ie in Aman, the GY and LY were different.

But how different? The last comment I can find on the point is way back in NoME 1.XII, before almost all of the genealogies, which baldly states: "It appears that in Aman the Quendi were little affected in their modes of growth (olmie) and life (coivie)," despite most other life in Aman aging as if 1VY = 1 sun-year, rather than 144. That contradicts the implication of XVIII, and moreover is not very helpful for the massive timescale I've been landed with!

But... the last comment before that appears in the notes to the same text, where a "prior" (per CFH) version of that passage said something slightly different: that the coivie remained unchanged in Aman, because it was already running at the Aman rate, but the olmie was slowed down.

I think that passage probably marks the best compromise between the various issues here. If the growth-years of the Eldar are 144 SY rather than 3 SY for the Aman era, then per XVIII it would take 3456 SY for an Aman elf to reach full growth. If they married and had their first children at full-growth, the third Aman generation just about exactly half-grown when the Trees died. That's Celebrimbor at least, and some combination of Orodreth, Finduilas, and Gil-Galad; that actually works pretty well? We know Galadriel was "not yet full grown", and this 3456-SY childhood might finally make sense of that.

hS