The word plastron is French, and derives from the term plate, indicating the piece of the armor that repaired the chest of the medieval knights.
This accessory, already from the Victorian era, is worn by making a particular knot, after which the flaps of this type of tie crossed to cover the shot of the shirt, are stopped with a pin.
It finds its maximum expression when worn with the shirt with diplomatic collar and with the tight.
The ultramodern plastron, on the other hand (smaller and already knotted), can also be worn with the shirt with traditional collar. It always maintains its charm.