On the road between Härkeberga and Skolsta stands a rune stone that tells the story of a person who actually lived in this very place, Kälsta, a thousand years ago. The rune stone has a cross, which means that the person who ordered it was a Christian, and it is believed to have been carved by the rune master Erik. Erik is considered to have been active around 1030-1050, at the end of what we call the Viking Age.
The text on the stone is interpreted as follows: "Lidsman and Toke erected this stone after Ågöt. He lived in Kälsta." The place name Kälsta (Kelsstǫðum) still live on today, after a thousand years.
Uppland runic inscriptions 755.
Nearby is the burial ground Trestensbacken.