If Denethor hadn't committed suicide

[PrinceOfTheHalflings]

Originally Posted by Inziladun

Ah, but was Thorongil the name he gave himself, or a name that was applied to him by others?

ROTK Appendix A

That gives the impression he was given the name 'Thorongil' as a reflection of men's observations about him. They had to call him something, after all.

I don't recall any mention of whether he was called Thorongil in Rohan.

Perhaps not. An Elvish name wouldn't mean much up there. He must have given some name when he first showed up in Minas Tirith. Of course, perhaps he gave the name that he had acquired in Rohan. At first, people in Gondor probably just knew that he'd come from Rohan and acquired some fame in Thengel's service - presumably 'Thorongil' came with some sort of personal recommendation from Thengel himself (although that's obviously just speculation).

Evidently people in general in Gondor had no clue where Thorongil was from originally. But a learned fellow like Denethor, who had access to all the ancient scrolls, would have been far better informed. He would almost certainly have been at least somewhat familiar with the history of Arnor. He knew about Imladris and Elrond. When Faramir and Boromir came to Denethor many years later with their portentious dream about "The Sword That Was Broken", "Imladris" and "Isildur's Bane" it might not have come as a complete surprise to Denethor that Rivendell might have some connection to the Old North Kingdom. Certainly Denethor seemed aware of what "Isildur's Bane" was and had instructed Boromir to do what he could to bring it to Minas Tirith.

I wonder how much Sauron learned from Denethor regarding this matter? Sauron would have expected someone like Saruman or Denethor to try to sieze the Ring, but he seemed quite surprised when Aragorn revealed himself as the Heir of Isildur in the palantir. Apparently Denethor hadn't given away anything concerning his suspicions about Aragorn!