Be-styrian

According to the Old English Dictionary:

be-styrian

p. ede; pp. ed [be, styrian to move] To heap up, pile up; aggerare :-- His þegnas mid moldan hit bestyredon and gefæstnedon his thanes heaped up with mould and fastened it, Bd. 3, 2; S. 524, 20. be-styrian