Did Vikings really wear horned helmets?

No, as far as anyone can tell. The horned Viking is a 19th-century invention. It was popularized by Richard Wagner's Norse operas, and in particular by the costumes Carl Emil Doepler designed for Wagner's Ring cycle in 1876, which included horned helmets.

The evidence from the Viking Age itself, roughly 800 to 1050 CE, points the other way. Texts from the period mention helmets regularly but never horns. Even Christian writers, who were eager to paint Vikings as barbaric, never mentioned them. And the few Viking helmets that archaeologists have found have no horns at all. The best preserved, found in Norway in 1943 by a man preparing to build a house for his parents, is a plain, rounded iron cap.

So where did the idea come from? Horned helmets did exist in Scandinavia, just not in the Viking Age. A pair of bronze horned helmets found in Denmark dates to around 1100–900 BC, nearly two thousand years before the first Viking raids. Later carvings and trinkets show horned figures too, but some scholars think these depict gods or rituals rather than battle gear.

Historians generally believe that if Vikings ever wore horns, it wasn't regularly. The myth has been debunked again and again, yet it survives because it is such a good picture. An opera costume, it turns out, can outlast a thousand years of evidence.