There are many designs of ancient Greek helmets depicted in surviving ancient pieces.
One of the most ancient ones is the Mycenaean helmet. Helmets evolved with time from simpler forms, made of a unique metal piece, to more complicated ones, made of two or more pieces, leaving openings for the ears and the mouth, making them more functional and accommodating to the warriors.
The Corinthian type is the most well-known type, although the Attic, Illyrian, Thespian, Spartan and Trojan were widely used as well.
Common soldiers (hoptiles) had simpler helmets, without decorations, while kings, higher officers and leaders had usually crested helmets, decorated with plumes, making the helmet functional and impressive at the same time.