The composition ratio of the coat of arms

Escutcheon in the Crest description.
Helmet.
The rate of coat of arms changes variously with the age.

Time.	Century.	shield	helmet	crest	mantling
Initial Gothicstyle.	12〜13	2	1	1	No.
The middle Gothic style.	14 begin	3	2	3	2
The middle Gothic style.	14 end.	2	2	4	2
The latter term Gothic style	15	3	2	3	4
The latter termRenaissance.	16	5	4	6	4〜5
baroque.Retrospection	17〜19	5	2	3	3〜5
The present day	20	3	2	3	4〜5

Modern crest art succeeds to latter term Gothic style harmony 3.2.3.
A armor comes in the middle of the coat of arms.