Stockholm County Museum runic expert Lars Andersson said a rock used to help mark the lot's boundaries is thought to date back to the Viking Age in Sweden, The Local said Friday.
Andersson said in a museum statement the discovery of runic inscriptions on the rock thanks to rainy weather was akin to a "religious experience."
"To read something that nobody else has read for 1,000 years is almost a religious experience," he said.
The rock was found last fall at the church outside Stockholm when the religious site had a nearby area excavated in order to lay some cables.
The Local said the rock, now thought to be a gravestone, was then used as a parking lot border as mud and earth covered up the inscription clues to its true history.