The helmet was used to protect the head, the neck, and the sides of the face. Depending on the type of helmet, it would eather protect more or less of the head and face. This particular helmet didn't have a face gard. Others have a face mask and only a small place to see through.
This armor was used to protect the entire body of a knight. The armor was exstreamly heavy so if the knights fell over or got nocked down in battle they usually could not get back up on their own.
