Why does Sauron face Gil-galad and Elendil at Mount Doom?

Question

I have been pondering this the last few days. I've heard many theories as to why the last contest of the battle of the Last Alliance took place at Mount Doom. Some people believe that Sauron headed there because the leaders of the Last Alliance (Elrond, Cirdan, Gil-galad, Isildur, and Elendil) may have been camped there, so Sauron went all out to take out the main guys. Karen Fonstad believes Sauron headed to Mount Doom due to the Ring being at its greatest when at the Sammath Naur.

I personally believe Sauron may have come forth and broken the siege for a while with his power but, eventually realising he was outnumbered, fled to Mount Doom and made his final stand against the leaders of the Last Alliance.

Is there any evidence as to why Sauron faced Elendil and Gil-galad at Mount Doom in Tolkien's texts?

Answer 1

This is never directly answered

I've found nothing in the text (either published or in Tolkien's drafts) to directly support any theory about why Orodruin was the site of the final confrontation. The only thing we're told is that Sauron broke the siege of Barad-dûr, and that he fought Gil-Galad, Elendil, and Isildur on the slopes of Mount Doom.

That being said, I find Fonstad's to be the most plausible; we're told of a couple of effects that might have made Sauron want to have his last stand there:

• The power of the Ring increases the closer it gets to Sammath Naur:

  As it drew near the great furnaces where, in the deeps of time, it had been shaped and forged, the Ring’s power grew, and it became more fell, untameable save by some mighty will.

  ^{Return of the King Book VI Chapter 1: "The Tower of Cirith Ungol"}

• Sauron's lingering power suppresses the effectiveness of other powers:

  [Sam] drew out once more the phial of Galadriel, but it was pale and cold in his trembling hand and threw no light into that stifling dark. He was come to the heart of the realm of Sauron and the forges of his ancient might, greatest in Middle-earth; all other powers were here subdued.

  ^{Return of the King Book VI Chapter 3: "Mount Doom"}

It's also worth noting that Barad-dûr and Orodruin are actually quite close together, going by the text; Sam observes the road between the two, which runs for only about a league (about 3 miles, or 5 kilometers) from the gate of Barad-dûr to the foot of Orodruin:

[H]e was looking at Sauron’s Road from Barad-dûr to the Sammath Naur, the Chambers of Fire. Out from the Dark Tower’s huge western gate it came over a deep abyss by a vast bridge of iron, and then passing into the plain it ran for a league between two smoking chasms, and so reached a long sloping causeway that led up on to the Mountain’s eastern side.

^{Return of the King Book VI Chapter 3: "Mount Doom"}

Answer 2

The Gorgoroth area, which encompasses Barad-dûr and Mount Doom, was the last stronghold of Sauron. Why Sauron fought Gil-galad and Elendil near Mount Doom rather than Barad-dûr is not specified.

The Silmarillion recounts the battle like this:

Then Gil-galad and Elendil passed into Mordor and encompassed the stronghold of Sauron; and they laid siege to it for seven years, and suffered grievous loss by fire and by the darts and bolts of the Enemy, and Sauron sent many sorties against them. There in the valley of Gorgoroth Anárion son of Elendil was slain, and many others. But at the last the siege was so strait that Sauron himself came forth; and he wrestled with Gil-galad and Elendil, and they both were slain, and the sword of Elendil broke under him as he fell.

As others have noted, Elrond says, in FOTR:

`I was the herald of Gil-galad and marched with his host. I was at the Battle of Dagorlad before the Black Gate of Mordor, where we had the mastery: for the Spear of Gil-galad and the Sword of Elendil, Aiglos and Narsil, none could withstand. I beheld the last combat on the slopes of Orodruin, where Gil-galad died, and Elendil fell, and Narsil broke beneath him; but Sauron himself was overthrown, and Isildur cut the Ring from his hand with the hilt-shard of his father's sword, and took it for his own.'

That's not a contradiction, since from this map we can see that Gorgoroth encompasses Mount Doom and Barad-dûr.

So it was all of Gorgoroth where Sauron made his last stand. We can only speculate as to why the battle between Sauron and Gil-galad / Elendil happened at Mt. Doom rather than somewhere else in Gorgoroth, unless History of Middle Earth provides additional details.

My first thought is that Tolkien put the fight at Mt. Doom in FOTR because it sounds more dramatic. Since the Silmarillion wasn't published, it didn't matter that the Silmarillion just says Gorgoroth .

For an in-universe explanation, I'd say that Sauron wasn't going to wait around in Barad-dûr, because that seems cowardly? Or maybe the Last Alliance forces were bombarding Barad-dûr, since it was destroyed in the battle, although I'm not sure if it was before or after Sauron's defeat.

Why Moon Doom then? Again, we can only speculate. Maybe the ring, as it got closer to the only place where it could be destroyed, would be harder for its possessor to resist its draw. Sauron could have been making it likelier for the ring to be used (therefore corrupting its wearer) in the event of his defeat.

Or, it could be simply because being high ground, it was the most strategic place for Sauron to make his last stand.

Answer 3

Sauron came forth, and sallied from Barad Dur. He probably tried to break through the beseigers and get to other fortresses or Places where he might have forces available to him. I see it as him breaking through the ranks of and camps of the Last Alliance, but was caught at Orodruin by the two kings who then duelled him.