Frog-mouth helm

The frog-mouth helm or Stechhelm (German, meaning stinging helmet) is a type of great helm, appearing from around 1400 to 1600, that was used by mounted knights. It also served as a heraldic symbol in its time. The Stechhelm formed part of a highly specialized tournament armor worn solely for the Gestech, or German joust, fought with blunted lances. The distinctive shape of the helmet served to protect the face of the person wearing it, and was intended to be used by a person on horseback. The ocularium of the helmet (the slit through which the wearer could see) had the appearance of a frog’s opening mouth, hence the name of the helmet. Older examples of the helmet were a single piece of metal, while those that are more recently dated had hinged constructions that could be disassembled.

History
Beginning in the 15th and 16th century in Germany, the frog-mouth helmet or Stechhelm, appeared as a style of great helm. It became popular for jousting, largely because the narrow and upturned eye slit greatly diminished the opportunity for pieces of a splintering lance to enter the eyes. The simpler construction of the helm was a single piece that had to be lowered onto the head from above. In the late 15th Century, it became customary for the helmet to be mounted with multiple screws onto the chestpiece. This variety could not be turned to look around the wearer. More expensive varieties had hinges and could be opened in the front for ventilation, while also "folding" around the wearer's head to put on and "unfolding" be removed. The helm had vents on the right side so it became easier for the wearer to breathe while using it, as well as allowing non-muted noise to enter into the helm. Underneath the helm, the wearer traditionally had a leather cowl to protect from concussive impacts. The cowl was attached with leather straps and cords fastened to the helmet, so that a certain degree of head movement was guaranteed. A popular jousting technique was, at the last minute, to pull the head up. This completely obscured the vision for the wearer, but it protected the eyes from the splinters of the lance as it broke on his armor.