Alexander and his granddad were out exploring the site of the Battle of Lund (1676) when the boy happened on some silver coins coated in verdigris. The buried treasure had likely come to the surface when the field in which they were wandering was recently ploughed.
A day later, archaeologists from the National Heritage Board arrived at the site with metal detectors and were quickly able to find two clay vessels containing more than 7,000 silver coins dating from around 1300 AD.
"I never thought I'd experience anything like this," archaeologist Mats Anglert told The Local.
The coins were primarily from Denmark and England, he said, although there were also a number of rare coins from parts of modern day Germany and the Netherlands.
"I suspect we may have doubled the number of English coins from the Middle Ages ever found in Sweden," said Anglert, who estimated that 1,200 of the coins had come from across the North Sea.
English sterling coins were used as something of a global currency at the time, said the archaeologist.
"The ones we found were in their own separate container," said Anglert.
He could only speculate as to why the vessels had been buried underground.
"We're going to continue digging now and hope that we find out more about the context surrounding the coins.
"Somebody probably buried it but we don't know why. In Viking times people often sacrificed money in religious rites but I doubt if it's that. This was a large fortune and the reasons were probably more financial," said Anglert.
As for Alexander Granhof, the boy who found the treasure: "He was somewhat overwhelmed," said Anglert.
"He was very enthusiastic and was able to help us out with the dig."