I can't remember where but I read somewhere that the sword of the king of Numenor was in fact Aranruth - the sword of Elu Thingol.
How is this possible? I assume that Dior took up Thingol's throne in Menegroth and may have inherited the sword, but would the sword have then been given to Elwing and then Elros? Given that he was a small child during the events of the 2nd Kinslaying in Doriath, wouldn't Maedhros, or the Naugrim, have taken the sword at some point?
Elwing was born in F.A. 503, and the Sack of Doriath (or the second Kinslaying) was in F.A 506. In Unfinished Tales it says that Elwing recovered Aranrúth (which was then subsequently given to Elros by Eärendil).
So, the question is whether you believe that Elwing would be capable of doing that at the age of 3 : fleeing Doriath, carrying Aranrúth and also a Silmaril. Elwing was pretty hardy, and elves do mature faster than humans - but I don't think that Elwing was entirely alone when fleeing the Doriath.
I have read that Nimloth, daughter of Galathil, escaped with Elwing - but there are also conflicting tales that Nimloth was killed in the battle.
Considering that Elwing arrived at the Havens of Sirion by sea, I think it is reasonable to assume that she was accompanied by at least one other that would have helped carry Aranrúth.
According to the Tolkien Gateway:
Elros, the first King of Númenor received it from his mother, and from there on it became an heirloom of the Kings of Númenor.
According to The Encyclopedia of Arda:
The sword of Thingol, King of Doriath and overlord of the Sindar. We know little of its origins or history, except that its name Aranrúth means 'King's Ire'. After Thingol's fall, it was rescued from the sack of Menegroth and taken south by the survivors in the keeping of Thingol's great-granddaughter Elwing. Elwing in turn gave it to her son Elros, who would become the first King of Númenor, and Aranrúth remained the sword of the Kings of Númenor after his time. The sword's final fate is uncertain: it may have been lost in the Downfall of Númenor, or Ar-Pharazôn may have taken it with him to Aman, in which case it still lies within the Caves of the Forgotten.
In response to the above:
From the book, I seem to recall that Ar-Pharazôn's pride had overwhelmed him by this point (encouraged and manipulated by Sauron), which led to the creation of the fleet known as the Great Armament. I don't think it is too much to suppose that Ar-Pharazôn would have without a doubt had the sword in his possession when the fleet left Númenor. I can easily imagine him believing that a weapon such as Aranrúth would be "destined" to fulfil such a purpose.
I know this is better suited to a comment, but please forgive me as I'm new around here and I can't technically leave comments just yet.
