A breastplate protects the front of the torso and along with the helmet comprise the nucleus of armour in general, protecting bodies most vulnerable areas.  When the breastplate is worn with a back plate, the torso pieces together are called the cuirass.

Roman Breastplate circa 100 BC

The classic muscular steel breastplate of ancient Rome provided excellent protection and as an added bonus, gave it’s wearer a heroic physique (rock hard six pack abs).  The Romans copied this design from the Greeks who originally created it in bronze.  The draw back to this solid one piece design is that it greatly restricts torso movement.

This segmented cuirass appeared in many times and cultures.  Relatively easy to build and quite flexible, this type of armour was practical, dependable and financially viable for the lowly man at arms.