The Volsunga Saga influenced The Silmarillion

Tolkien was a professional philologist working on exactly this material, and the Silmarillion takes its architecture from it: a cursed treasure that destroys everyone who holds it, a dragon guarding hoard and speaking with its victim, a hero who kills that dragon from below, and a family destroyed across generations by an oath. Túrin Turambar is Sigurd crossed with Kullervo, and Tolkien said so;