Eventually Helmets made improvements and a full face guard was created. The conical helmets became a cylinder with a round top. Eye slits and breathing holes were added. Typically the Great Helm was worn over a smaller helmet, which was worn over a cloth arming cap.
The Sugar Loaf Helm was an improvement over the flat top Great Helm. Although, the Great Helm offered greater protection over the face the round flat top was susceptible to impact from blunt weapons. Interestingly, the conical helmets of the early centuries offered greater protection of the overall head than the flat top Great Helm.
The rounded design of the conical helmet would deflect the greater force of a blow to the head. The Sugar Loaf Helm now offered the protection of both the conical helmet and the Great Helm. Both the Great Helm and the latter Sugar Loaf Helm were helmet of the Crusades.
This is an almost exact replica of the Sugar Loaf Helm worn during the 13th century.