answer:The closest thing to an actual horned helm that comes closest to the Viking area was probably the Vikso Helmet Unfortunately for fans of Hagar the Horrible, it predates the Viking age by over a thousand years. Then there’s this British thing from 700 years-ish pre-Viking. And THEN, if you really push it, there’s this decoration from the Sutton Hoo helmet At least that’s only pre-dating the Vikings by 200 years, but it is depicting ritual bird-headdresses on a helmet that has no horns at all. This is the only actual example of a Skandinavian-made helmet found in Skandinavia that dates from the Viking age. Note the lack of horns. Basically, what happened was a case of musical theatre. Wagner took Greco-Roman descriptions of barbarians (note: Greece and Rome were both kaput as empires long before the Viking age) wearing ritual horned helmets, and ran with it for costuming for his operas. And, Bob’s your uncle, generations of people grow up thinking Vikings wear helmets while they sing about trying to kill the wabbit.