Great Helm Brass Decorations

The image displays a replica great helm, also known as a pot, bucket, or barrel helm, which was a popular style of helmet used during the High Middle Ages.

This type of helmet evolved in the late 12th century and was widely used by knights and men-at-arms in most European armies until the 14th century.
It provided greater protection for the head and neck compared to earlier open-faced helmets and was notably worn by knights of crusading orders such as the Knights Templar.
The helmet in the image appears to be made of steel with a decorative brass cross application on the front.