Did they find the soldier that was holding it?
FTA: In the coming days and weeks, archaeologists will carry out limited excavations at the peat bog where the sword was found; the researchers are hoping to find the missing elements of the knight’s equipment, and other clues that could explain how the weapon ended up where it did.
“how the weapon ended up where it did”
My guess: Somebody chucked it in there to dispose of it.
For one reason or another.