Final answer:
The statement is false, as the passage does not mention the dragon being overcome by the sword of their mouth and an iron rod.
Step-by-step explanation:
The statement is false. The passage provided describes a champion named Ethelred who defeats a dragon by striking it with a mace. There is no mention of the dragon being overcome by the sword of their mouth and an iron rod. The passage focuses on Ethelred's triumph over the dragon using his physical strength and weapon.