The Volsunga Saga influenced The broken sword

Anderson wrote a saga rather than a novel about one, and the borrowings are structural:

• A sword broken and reforged as the hinge of the plot, which is Sigurd's Gram
• A blade that must kill whenever it is drawn and turns on its owner, the Tyrfing curse
• A changeling, a doomed hero raised away from his kin, and incest discovered too late, all of which the Volsungs supply
• The saga voice itself: flat, fast, fatalistic, and offering no interiority

Published the same year as The Fellowship of the Ring and drawing on the same Norse source Tolkien taught, which is why the two books read as opposite answers to one question.