system
Given the following post, respond as if you're commenting on Reddit:
human
[LotR] Did Sauruman know that Gandalf was the keeper of Narya?

I'm not sure if Gandalf could hide it from a fellow wizard, but it also seems like Sauruman would have treated Gandalf as a greater threat if he knew he had one of the Three Rings.
gpt
Unfinished Tales:

> And the Grey Messenger took the Ring, and kept it ever secret; yet the White Messenger (who was skilled to uncover all secrets) after a time became aware of this gift, and begrudged it, and it was the beginning of the hidden ill-will that he bore to the Grey, which afterwards became manifest.