Isengard- Help Wanted!

[Inziladun]

After recently re-reading TTT, I was wondering about a relatively small bit of dialogue from the mouth of Saruman, directed at King Théoden when Gandalf confronted Saruman at Isengard.
After Théoden turned down flat Saruman's proposal of an alliance between himself and Rohan, Saruman became rather irate, and said to the king:

'Long ago I offered you a state beyond your merit and your wit. I have offered it again, so that those whom you mislead may clearly see the choice of roads.'

That is curious, especially in light of the fact that Théoden wants to come to Orthanc with Gandalf to 'speak with the enemy who has done me so much wrong'. That suggests Théoden had not actually spoken with Saruman before.

So what could Saruman have meant? What did he offer to Théoden, and how?