Y'all had to know that this post was coming, eventually.
It the develoment of the Lord of theRings, the first mention of Éowyn called her the daughter of Théoden. That was quickly changed, but for some time there was another character named Idis who was Théoden's daughter, and older then Éowyn. Curiously, she didn't actually do anything; when she appeared at the great hall in Edoras she just stood there, while Éowyn brought the wine etc. As Christopher said:
I cannot say what function in the narrative my father had in mind for Idis ... ; still less why the daughter of the King (and older than Éowyn should be so silent and so overshadowed by the niece).
Originally, Aragorn and Éowyn both fell in love with each other (Arwen did not yet exist). In an early outline, Tolkien actually wrote "Aragorn weds Éowyn sister of Éomer." Christopher then writes:
But the story of Aragorn and Éowyn would in the event, of course, be quite otherwise, and; and in another short group of notes, isolated and undateable, this marital alliance of Rohan and Gondor was rejected (and no other was foreseen):
?Cut out the love story of Aragornand Éowyn. Aragorn is too old andlordly andgrim. Make Éowyn the twin-sister of Eomund, a stern amazon woman. ...
Probably Éowyn should die to save Théoden.
But my father added in a hasty scribble thepossiblity that Aragorn did indeed love Éowyn, and never wedded after her death.
I find the fact that Tolkien considered making Éowyn an "amazon woman" significant. In a later note, in response to Théoden's noting that he did not have enough Riders to save Minas Tirith:
Éowyn says that women must ride now, as they did in a like evil timein the days of Brego son of [mark showing name omitted] Eorl's son, when the wild men of the East came from the Inland Sea into the Eastemnet.
I think I would have liked to have had this concept remain in the story.
An early outline shows that the conception of Éowyn being part of the battle against the Witchking existed from an early point, though the original conception was quite different then final story:
3. Charge of the Riders of Rohanbreaks siege. Death of Théoden and Éowyn in killing the Nazgûl King.
It appears that in the earliest conceptions of the story, Éowyn rode openly to Minas Tirith, not in disguise:
Against March 10 (?) is written: 'Merry insists on going towar and is taken up by [Grim>] Dunhere who rides with the King,Éowyn and Éomer.' It is hard to know what to make of this. A possibility is thatmy father had briefly decided toabandon the story of the 'yong rider of the guard (Éowyn), for Éowyn will now come openly to Minas Tirith, while Merry, equally openly, is taken by Dunhere, chief of the men of Harrowdale. In support of this isthe abandoned name Grim-(for Grimhelm?), and perhaps the underlining of Éowyn. But this seems to me very unlikely. It seems more probably that this text represents earlier ideas for this element in the story: not only is Merry permitted to go with the host, but Éowyn rides also as a matter of course.
It is interesting to me that Tolkien originally planned to have Éowyn openly come to Minas Tirith (as an 'amazon woman') and then perish in the defeat of the WitchKing. What a different message the final version of story makes!
Another interesting point of note is that once the story develops to the point where Éowyn survives the encounter with the Witchking, it is Aragorn, not Gandalf that originally describes what it must have been like for her during the decline of Théoden (but he still adds to Éomer about Éowyn's love for him "I saw also what you saw. An few other griefs amid the ill chances of the world ...").
After all this, Éowyn and Faramir's relationship seems to spring full-formed into the tale as if it had been planned all along. Tolkien notes in an outline when he was writing the Field of Kormallen:
The wedding of Aragorn and Finduilas (Arwen's original name)
Also Faramir and Éowyn.
Christopher notes that the Chapter The Steward and the King, "though written roughly and rapidly, was changed very little afterwards." After all of Tolkien's doubts and changes of direction, it seems that Éowyn's love for Faramir, and her conversion from "amazon" to happy homemaker was the most natural thing of all.
"Spirits in the shape of hawks and eagles flew ever to and from his halls; and their eyes could see to the depths of the seas, and pierce the hidden caverns beneath the world."