`` Heimskringla '' tells of how when king Halfdan the Black of Vestfold died Death his son Harald was still only a child of ten .

He split Destroying his army in two , one force led by his son Hake was to advance Self_motion on land , while the other , led by Gandalv , was to cross Self_motion the sea and attack Attack the Vestfold army from the rear .

After the battle Hostile_encounter Guttorm turned Change his forces Causation to face Confronting_problem the army of king Gandalv that had landed Arriving in Vestfold , further south .