Olof Eriksson skotkonungr (c. 980-1021) is the first man of whom historical sources of adequate quality tell that he managed to get himself elected king of both the Götar and the Svear. These tribal groups had previously been organised separately, and thus Olof may fairly be seen as the first king of Sweden as we know it.
Olof’s main power base was the town of Sigtuna between Stockholm and Uppsala, founded by his father King Erik as a Christian replacement for the pagan trading post on Björkö (Biaerkey, latinicised Birca). Sigtuna was the site of Sweden’s first known mint, where English minters worked on a small scale, producing coins bearing Olof’s name but ripping off Ethelred’s designs. These coins are rare, so when six were recently found on Gotland it expanded the corpus considerably.
The new hoard is a small one for Gotland: only 54 coins all in all, tpq AD 1009, found during excavations after a home-owner in Bunge parish alerted the authorities to coins he’d found in his flowerbeds. As is common in 11th century hoards, the bulk is English and German coins.
Olof’s coins are so rare that they can’t really have functioned as legal tender. You can’t have a legal tender system if coins are so scarce that many people don’t know what they should look like. This suggests that Olof wasn’t striking coins for reasons of economic rationality. They were most likely part of propaganda efforts by this princeling on the periphery, proclaiming proudly that he was the Ethelred of the North, a real Christian king. Little did he know how posterity would value Ethelred the Unready.