[Mithalwen]

Theodred was an exact comtemporary of Boromir. They were the same age and ie within hours of each other. There is more on his valiant death and background in Unfinished Tales if you haven't read it yet. I would need to check HoMEfor the origins, but I think Theodred exists to strengthen the paralels and contrasts between Gondor and Rohan. Theoden and Denethor have both lost their sons and are under a malign force but while Theoden is healed by Gandalf and is roused to fight, Denethor yelds to despair refusing to fight and tries to take Faramir with him. It perhaps also gives a symbolic fresh start across the board in that the day that Aragorn arrives in glory at Minaa Tirith, there is a new King of Rohan and a new steward neither of whom were heir apparent.