Per Hellstedt was a great nyckelharpa player from Tobo in the province of Uppland. He was born in 1771, the son of another harpa player, and died in 1850. He was the great-uncle of the famous fiddler August Bohlin.
This brudmarsch (bridal march) named for him is one of the most played nyckelharpa tunes in Uppland.
I myself learned this tune just playing with Uppland fiddlers in 1974. My nyckelharpa version of it is inspired by my experience playing it with the greatest harpa player of them all, Eric Sahlström.
Here is a YouTube recording of Sahlström playing it on nyckelharpa in 1960.
Here is a video of me playing Per Hellstedts Brudmarsch on the fiddle.