Dol Guldur

[Gordis]

Originally Posted by Legate of Amon Lanc

Nay, why would he do that? Sauron might have guessed it, or forced it out of him, possibly, but Saruman had no need to tell him from his own initiative. Saruman was very clever and aware of the fact that having more knowledge than those around him is always advantageous for him.

Why would he tell Sauron? - to position himself as a powerful ally, not a lowly servant, Saruman had to impress Sauron with his power. Also, I am almost sure that the two Maiar had been quite well acquainted while they both were in the train of Aule in Valinor - like two post-docs of the same professor. It may well be that Curumo's admiration and envy for Sauron dates back to these times.

That's possible. But it's also possible that Sauron simply was not strong enough yet back then and even though not knowing who he is, he felt him powerful (something like if Elrond came there) and so he decided to escape. Gandalf had already quite some time of his actions in M-E, so Sauron might have learned about him being a powerful figure, and he did not necessarily have to know who he was.

In the case of Gandalf, Sauron may have indeed not known him as Olorin before. However, it is quite possible that he recognised him as another incarnate Maia. He wouldn't be so impressed if Elrond came there, I believe.

As for the Witch-King, he surely was aware of Gandalf's power. The WK may or may not have known that Gandalf was a Maia; however, given his extensive experience with Sauron, I believe he would know a Maia when he saw one.