Danish National Museum spokesman Jens Christian Moesgaard says the coins have a distinctive cross motif attributed to Norse King Harald Bluetooth, who is believed to have brought Christianity to Norway and Denmark.
Sixteen-year-old Michael Stokbro Larsen found the coins and other items with a metal detector in a field in northern Denmark.
Stokbro Larsen, who often explores with his detector, said friends find him "a bit nerdy."
Moesgaard said Thursday that it was the first time since 1939 that so many Viking-era coins have been found, calling them "another important piece in the puzzle" of history.
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