Approximately one kilometer north of the castle ruin in Näs is a solitary oak. This oak is called Sverker’s oak.
According to a myth, King Karl Sverkersson was murdered here in Easter in the year 1167 A.D. He was on his way to his castle in Näs after visiting Ströja kyrka (Ströja church). The body of the dead king is supposed to have been tied to a thousand year old oak, which grew at this site until 20th Century. The oak you see today was planted 1956 by Visingsö Hembygdsförening.