taken from the on-site information board:
All four rune stones found in the vicinity of Haithabu are memorial stones for fallen warriors who were closely related to the Danish rulers of the 10th century in Haithabu.
A fifth rune stone, dated around 1050, was discovered in 1897 in the north side tower of Schleswig Cathedral. Today it is in the Gottorf Castle Archeology Museum.
The Erik stone indicates the followers of King Sven Gabelbart (approx. 987-1014). Sven’s follower Thorulf had this stone erected in memory of his comrade Erik, in order to praise his merits as a skipper and warrior.
The rare tie runes on the back of the stone are a specialty.