Here's a slightly terrifying thought: When Cennini says when you are caused to make a crest or helm, his leather moulding process may actually create a SCA legal equestrian helmet.
http://www.noteaccess.com/Texts/Cennini/index.htm
'Whenever you have occasion to make a crest or helmet for a tourney, or for rulers who have to march in state...'
I had really only read the wording about crests, and glossed right over his mention of making helms using the same process.
The SCA Equestrian handbook says:
'A. Equipment Standards: All equipment must be inspected for use prior to engaging in equestrian combat activities.
1. Armor requirements:
(a) Helm.
(1) Helms must be of rigid materials (18-gauge mild steel or equivalent). Fencing masks are acceptable for mounted crest combat use only.
...
B. Glossary.
1. Rigid material: a. Steel of no less than 18 gauge, or aluminum of no less than 1/8-inch (3mm)....
d. Heavy leather (as defined above) that has been hardened in hot wax, soaked in polyester resin (properly catalyzed), or treated in such a manner as to permanently harden the leather.
e. Two layers of untreated heavy leather.'
It also lists:
'2. Non-brittle: Shall refer to material that will not break or shatter upon being subjected to a stiff strike.'
This implies that although a full helm may be made from Cennini's leather method, the gesso layer could be deemed brittle and unsafe by the Kingdom Earl Marshall.
Fortunately for the sane among us, the Lochac Equestrian page recommends nationally recognised modern helmets are worn at all times while riding. Thanks for looking out for us, Lochac. Perhaps Cennini was saying that this process could be used to create a helm and accompanying crest for parades, where the person would be marching or the helm would be on display. I am going with that option for now.
