Sappers in Trench Armour

These two sappers from the Imperial Guard Corps of Engineers are wearing trench armour.

The cuirass and the heavy helmet familiarly called pot-en-tête would protect sappers when they had to dig trenches under possible enemy fire.

Soldiers wearing helmets and cuirasses and digging trenches probably seem at first like an oddity to who is not overtly familiar with the Napoleonic wars. Yet, this hidden part of battles and sieges can be traced back at least to the Middle Ages -- when men would dig trenches or saps to approach covertly an enemy's besieged fortifications often to detonate a mine under them so that a wall would collapse opening a breach -- and would be part of any major conflict up to today.