Great helm
The great helm or heaume began as a cylindrical helmet reaching almost to the shoulders and gradually became tapered and developed a tapered visor. It has sights and breaths and in it's early years, may have a cross shaped reinforcement on the faceplate. It may sport a crest on it's early forms.
Development
The great helm developed over a period of 20 years from around 1220 from the flat topped helms popular in the the late 12th century. After about 1260 the top began to develop a taper.
Between 1300 and 1340 many great helms are shown with visors (such as in the Luttrell Psalter from 1340.
This type of helmet remains in use thoughout the 14th century although after about the middle of the century its use remains primarily in tournaments.
Under the Helm
This is worn with a padded coif which could sit either under or over a mail coif, or an arming cap which had a roll of padding around the brow. It could also be worn over a basinet.
