Napoleonic era. A type of heavy cavalry that got its name from the cuirass, the French word for breastplate. The idea was large men upon powerful horses, who were able to charge head-on into the enemy and expose and flanks or holes left in the lines of infantry after an artillery barrage. They were equipped with a cuirass, a long sword, two pistols and eventually a carbine.
After the artillery finsished its barrage, the cuirassiers charged the brokenlines of infantry.