Certainly Boromir, Legolas and Aragorn knew that Gollum was a ringbearer;
Know also, my friends, that I learned more yet from Gollum. He was
loth to speak and his tale was unclear, but it is beyond all doubt
that he went to Mordor, and there all that he knew was forced from
him. Thus the Enemy knows now that the One is found, that it was long
in the Shire; and since his servants have pursued it almost to our
door, he soon will know, already he may know, even as I speak, that we
have it here.'
All sat silent for a while, until at length Boromir
spoke. "He is a small thing, you say, this Gollum? Small, but great in
mischief. What became of him? To what doom did you put him?" "He is
in prison, but no worse," said Aragorn. "He had suffered much. There
is no doubt that he was tormented, and the fear of Sauron lies black
on his heart. Still I for one am glad that he is safely kept by the
watchful Elves of Mirkwood. His malice is great and gives him a
strength hardly to be believed in one so lean and withered. He could
work much mischief still, if he were free. And I do not doubt that he
was allowed to leave Mordor on some evil errand." - LOTR : FOTR
As did Gloín (and possibly his men too);
Glóin rose and bowed, and Legolas continued. 'In the days of fair
weather we led Gollum through the woods; and there was a high tree
standing alone far from the others which he liked to climb. Often we
let him mount up to the highest branches, until he felt the free wind;
but we set a guard at the tree's foot. LOTR : FOTR
Sam obviously knew;
“It doesn't sound as if he knew we were here, does it? ' whispered
Sam. ”And what's his Precious? Does he mean the...'
“Hsh!' breathed
Frodo. ”He's getting near now, near enough to hear a whisper." LOTR : TTT
And Gimli, Glorfindel, Erestor, Erestor and Galdor (and everyone else who was at the "Council of Elrond":
He then pointed out and named those whom Frodo had not met before.
There was a younger dwarf at Glóin's side: his son Gimli. Beside
Glorfindel there were several other counsellors of Elrond's household,
of whom Erestor was the chief; and with him was Galdor, an Elf from
the Grey Havens who had come on an errand from Círdan the Shipwright.
There was also a strange Elf clad in green and brown, Legolas, a
messenger from his father, Thranduil, the King of the Elves of
Northern Mirkwood. And seated a little apart was a tall man with a
fair and noble face, dark-haired and grey-eyed, proud and stern of
glance.
"Very well," said Bilbo. "I will do as you bid. But I will now tell
the true story, and if some here have heard me tell it otherwise" – he
looked sidelong at Glóin – `I ask them to forget it and forgive me. I
only wished to claim the treasure as my very own in those days, and to
be rid of the name of thief that was put on me. But perhaps I
understand things a little better now. Anyway, this is what happened.'
To some there Bilbo's tale was wholly new, and they listened with
amazement while the old hobbit, actually not at all displeased,
recounted his adventure with Gollum, at full length. He did not omit a
single riddle. LOTR : FOTR
and Faramir:
“He is lured here, you say? ' said Faramir in a low voice. ”Can he,
does he then know of your burden? ' “Indeed yes. He bore it himself
for many years.” 'He bore it? ' said Faramir, breathing sharply in his
wonder. "This matter winds itself ever in new riddles. Then he is
pursuing it? ' LOTR : TTT
Oh, and big S knew;
Sauron released [Gollum] and sent him forth... He did not trust
Gollum, for he divined something indomitable in him, which could not
be overcome … except by destroying him. But Sauron perceived the depth
of Gollum's malice towards those that had “robbed” him, and guessing
that he would go in search of them…, Sauron hoped that his spies would
thus be led to the Ring.
…Sauron had never paid heed to the “Halflings,” even if he had heard
of them, and he did not yet know where their land lay. From Gollum,
even under pain, he could not get any clear account, both because
Gollum indeed had no certain knowledge himself, and because what be
knew he falsified. Ultimately indomitable he was, except by death, as
Sauron did not fully comprehend, being himself consumed by lust for
the ring. … [Gollum] dared to pretend that he believed that the land
the Halflings was near to the .places where he had once dwelt beside
the banks of the Gladden. Unfinished Tales
