While Swedish Viking hoards are often found on the Baltic island of Gotland, they are much less common on the mainland.
Once thoroughly studied, the hoard "will give us lots of information about the journey it made and also ideas about why it was left in the ground," Beckman-Thoor said.
The Arlanda airport find might represent either loot from raids or profits from trade, she added.
Jonsson, of the University of Stockholm, favors the latter explanation.
"I think it's 95 percent trade," he said, adding that Vikings likely exchanged the coins for goods such as slaves, iron, tar, and amber.
While Vikings are documented to have traveled as far as the Middle East, most of this overseas trade probably took place in towns in Russia, a country rich in Viking remains, he said.
Most of the coins in the newfound hoard had been cut into pieces, Jonsson said, and the Vikings would have valued them principally for their 95 percent silver content.
"They put it on a scale and measured it and the weight gave the value of the silver," Jonsson explained. "They broke it into pieces to get exactly the amount of silver they needed."
The stone burial chamber where the hoard was found is being excavated before a new housing development is constructed on the site.
Measuring 52 feet (16 meters) in diameter, the Bronze Age tomb is thought to be around a thousand years older than the buried silver.
Only a handful of Viking hoards have previously been discovered hidden within such prehistoric monuments.
It may be that the prominent burial stones were used as a landmark by Vikings who intended to come back for the silver, Beckman-Thoor said.
"Or perhaps they thought their ancestors would protect the hoard, or perhaps it was an offering for their ancestors," she said.
The site of a medieval settlement lies below the hill where the stone monument is located, Beckman-Thoor noted.
"We believe the village goes back to the Viking age," she said.
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