The Ring and the Rings
A quote to get you interested:
Tolkien refused to admit that his ring had anything to do with Wagner’s. “Both rings were round, and there the resemblance ceased,” he said. But he certainly knew his Wagner, and made an informal study of “Die Walküre” not long before writing the novels. The idea of the omnipotent ring must have come directly from Wagner; nothing quite like it appears in the old sagas.