RomanArmyTalk

Hi, I am new here. I recently rekindled my interest in Roman history when I bought a reproduction helmet for my little brother ad figured I'd buy myself one as well.

I am sure this is a commonly asked question, however I cannot find an answer on google; what was the function of the band on the Galea helmet? 

I doesn't appear to be a sun visor, nor have any practical function that is apparent, unless perhaps it was used as a mount for an additional part of the helmet.

as I understand, it provides an impediment to downward slashes of swords to the helmet

Also as a weapon to head butt with 
Regards Brennivs 

As well as deflecting downward slashes away from the face, it also helps spread the force of the blow around a wider area of the helmet, thus reducing the force and therefore the damage at the specific point struck.

Crispvs