At the weekend archaeologists from the state of Mecklenburg-Western Pomerania excavated an area of about 400 square metres in an open field near the Rügen village of Schaprode.
To their surprise, they discovered Viking Age necklaces, rings, bracelets, beads, brooches, and 500 to 600 partially split coins - 100 of which are from a period in the late tenth century during King Harald's rule.
"This is the largest single find of Bluetooth coins in the southern Baltic Sea region and is therefore of outstanding importance," excavation director Michael Schirren said.
With a weight of 0.3 grams, the silver coins bearing a Christian cross were among Denmark's first independent coins.
Similar types of coins have so far only been found in the territory of the Danish empire, such as at Husby and Harndrup, according to the excavation director.
Harald Bluetooth is regarded as the founder of the Danish empire in that he brought the previously fragmented country together, implemented reforms and introduced Christianity to Denmark.
In 1872 and 1874, only a few kilometres away on the island of Hiddensee, gold jewellery also attributed to the king was discovered. It's possible there is a connection between this find and the one at the weekend, according to Schirren.
In January, hobby archaeologist René Schön and pupil Luca Malaschnitschenko had been searching for treasures with a metal detector on Rügen.
Little did they know that the piece of aluminium they found would prompt a team of archaeologists to search the area and uncover more treasures from the late tenth century.
"That was the find of my life," Schön said.