What does Herman mean?
From Germanic 'heri' (army) and 'man' (man), giving 'man of the army, soldier'. The Latinized Arminius refers to the same Cheruscan war-leader.
What does Walter mean?
From Germanic 'wald' (rule, power) and 'heri' (army), giving 'ruler/commander of the army'. Brought to England by the Normans.