Éomund of Aldburg was a prominent Rohir Thane who served as the Chief Marshall of the Mark under King Théoden Ednew of Rohan (r.T.A. 2948-3019). An extremely brave and somewhat rash Warrior, he was renowned for his skill as a horseman, which was no mean feat among the Riders of the Riddermark. He hated the Orcs that threatened the horse herds of Rohan's East-mark and hunted them relentlessly until his death in T.A. 3002. The Orcs, of course, both feared and hated Éomund, and it was an Uruk trap and ambush that claimed the Marshall's life.
Éomund's wife, Théodwyn, died of grief soon after his death. King Theoden adopted their two children—Éowyn and Éomer— and raised them as his own. Thus, Éomund's son eventually became heir to the throne of Rohan and ruled the Mark as the first King of the Third Line.