Does anybody know where the misconception of horns on viking helmets did arise from?

Prehistoric figures of men in horned helmets had been found in Scandinavia in the 18th century. Perhaps, with the hazy idea of prehistoric chronology, these gave the idea of horned Vikings, which was built on through art and opera in the 19th.century?

These are from Grevensvænge in Denmark

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Horned helmets were pretty common in the Bronze Age in Europe, the Aegean, and the Middle East. Later, they turn up in Asian cultures such as Japan.