A knight rides on campaign accompanied by a young man of noble family who keeps his equipment in order. What was that young man's position?

Explanation

The advanced stage of knightly training placed a young nobleman at a particular knight's side, responsible for his armour, weapons and mounts, and it took him on campaign where he could watch war at close quarters. Calling him a page fails because the earlier stage was spent within the household learning manners and basic skills rather than travelling with an army.