It's a logo of Armored Helmet reduced to a picture of small mid evil helmet. The helmet goes on top of people's heads often paired with a suit of armor for protection during battle. It is like a bike helmet but covered in metal and has face guards as well.
Related to Spartan Helmet Icon
Related icons are the icons with matching tags, as well as all military icons. All icons are in the same flat style. You can either download free PNG icons or buy SVG vectors