Like the medieval Knight's body Armor, the knight's Helmet also evolved as technology, battle tactics, and the Knight's role in society changed.
Among the earliest medieval Knight Helmets are the Norman Helmets of the 10th and 11th centuries. The Norman Helmets offered a conical top (usually) and a nasal bar piece of metal extending down from the front of the Helmet to protect the wearer's nose.
Around the late 12th Century helmets began covering the whole face. Air holes were created to assist the knight's breathing and eye slits offered a limited, but safer, field of vision. Around this time another "great" helm was developed: the Sugarloaf Helm. The Sugarloaf featured a conical top which could more easily deflect blows. Despite the added protection, the main drawbacks of the great helms (ventilation and visibility) encouraged the development of helmets with liftable visors.
Around the early 14th Century wealthy Knights had the alternative of wearing a Helmet with a movable visor. This attribute enabled a Knight to preserve a fairly full line of vision as well as greatly enhanced oxygen. Prior to battle, a knight could possibly shut the visor and also obtain the complete facial defense afforded by great Helms.
By the late Center Ages Knights' Helmets were a combo of field of battle utility as well as artwork. Certainly, by the end of the Center Ages (late 15th-early 16th Centuries) Helmets had come to be ritualistic in look-- a reflection of the Knight's new duty in society. These ritualistic style Headgears are frequently awesome in their craftsmanship and artistic features.