Helmet boss from the Roman site at Newstead (Trimontium), 80 - 180 AD
Use
Helmets were used to protect the head from sharp and blunt force trauma. Helmets could also denote the status and military rank.
Context
Some Roman helmets, such as Imperial Gallic helmets, have circular brass bosses. These bosses can be decorative or may have originated from Etruscan helmets from the sixth century BCE, which had bosses filled with lead to deflect blades