"Olórin I was in my youth in the West that is forgotten": what is forgotten?
Inspired by this question (which in turn was inspired by that one), to what name does "that is forgotten" apply to?
Many are my names in many countries: Mithrandir among the Elves, Tharkûn to the Dwarves; Olórin I was in my youth in the West that is forgotten, in the South Incánus, in the North Gandalf; to the East I go not.
J.R.R. Tolkien, The Lord of the Rings, The Two Towers
There are currently two competing top answers: the first one says that his "youth in the West" is now forgotten, because it was so long ago and in a different place, or "the West", because it is unreachable and mythical to humans.
How should this sentence be parsed?
For people unfamiliar with the Lord of the Rings, the person speaking in the quote is Gandalf. Gandalf is a lesser God (an angel, or Maia) who might have been born "outside" the world. He spent his "youth" (Maiar do not age, but they can grow in experience and wisdom) in "the West". In a sense, his youth happened either before Earth was created, or in its infancy.
The West is the name given to a continent (Aman, The Undying Lands) that was once west of Middle-Earth, on the other side of the sea. This is where the Gods live. By the time the story takes place in the Lord of the Rings, this continent has been removed from the world, so that
those that sailed far came only to the new lands, and found them like to the old lands, and subject to death. And those that sailed furthest set but a girdle about the Earth and returned weary at last to the place of their beginning; and they said:
'All roads are now bent.'
The Silmarillion
In this sense, both can be considered "forgotten", either from a time, space or knowledge point of view.
Although it might be a mistake from the translator, the French translation applies "forgotten" to "youth", not West:
Mes noms sont nombreux dans de nombreux pays, disait-il. Mithrandir chez les Elfes, Tharkûn pour les Nains ; j'étais Olorin dans ma jeunesse dans l'Ouest, qui est oubliée, Incanus dans le Sud, dans le Nord Gandalf ; dans l'Est, je n'y vais pas.
I know Tolkien was very protective of his texts and would actively verify translations. He also knew French.
Simply in the context it is given, it means that the West was forgotten: he immediately proceeds to mention north, south and east. I can see how one can assert either, but there is a very strong pull towards the cardinal directions in the sentence.
In the greater context of the mythology, West is often a synonym for Aman. Additionally, the only place he was known as Olórin was in Aman.
However one can plausibly assert that he means Beleriand, which used to be the Westernmost extent of Middle Earth until after the overthrow of Morgoth and the world was changed. Beleriand is now under the sea and the Western shore of middle earth when Gandalf is speaking is actually the easternmost extents of Beleriand from the First Age, more or less.
Note also that Gandalf/Olórin is a spirit who existed outside of time before the making of the world. Youth doesn't really have meaning for him.
The modifier "that is forgotten" is a restrictive relative clause, which we can tell from the facts that commas do not set it off and "that" is used rather than "which". A restrictive relative clause has the effect of restricting the reference -- that is the meaning of the term "restrictive". If a reference is already unique, it obviously cannot be further restricted, so restrictive relative clauses cannot modify nominals whose reference is already unique.
How many things could "my youth in the West" refer to? Just one -- Gandalf's young life happened just once -- so that is a unique reference.
What about "West"? That is less obvious. West the direction? West the territories lying in that direction? West a place of myth rather than an existing land? Whatever it means, to interpret the force of the restrictive clause, it seems we have to imagine "West" as having variable reference, so we can single one out as being the one that is forgotten.