It's the question Lord of the Rings viewers have been asking ever since Peter Jackson's trilogy came out: Why didn't Frodo and the Fellowship just ride eagles into Mount Doom? The reasons are fairly simple.

The War of the Rohirrim takes place about 250 years before the events of The Lord of the Rings, during the reign of Helm Hammerhand, king of Rohan. Or, to give you another kind of perspective on things: Helm’s Deep, the massive mountain fortress where the climax of Peter Jackson’s The Two Towers takes place? That’s named after Helm.