An illustration from

An Armenian Lectionary
of Cilician Armenia, 1286AD
The Descent from the Cross

Matenadaran Collection MS979

Note the soldier in helmet with ventail behind Pontius Pilate.
Lectionary (MS979)
E. Korkhmazian, I. Drampian, G. Hakopian, "Armenian Manuscripts of the 13th and 14th centuries", Matenadaran Collection, Leningrad, 1984
The Descent from the Cross
Date: 1286
Place: Cilicia
Current Place: Matenadaran (Yerevan)
Material & Size: Parchment, 33.5 X 24.5 cm

This manuscript referenced as figure 251 in The military technology of classical Islam by D Nicolle
251. Manuscript, 1289 AD, Armenian Cilicia, Matenadaran Lib., Ms. 979, Yerevan (Dou).
Bayḍah Helmets by David Nicolle, extracts from The military technology of classical Islam

Other Armenian resources:
The Armenians By Steven Lowe
Armenians on Surb Khach Church of the Holy Cross, Akdamar Island, Van Province, Turkey, c.920
Possibly an Armenian Infantryman in a Coptic Gospel, Damietta, Egypt, 1179-80
The T'oros Roslin (or Sebastia) Gospels of Armenia, 1262
Armenian Soldiers in Pseudo-Callisthenes’ History of Alexander the Great, c.1300–1325AD
An Armenian Gospels of Cilician Armenia, Matenadaran Collection MS7651, 1320AD

Illustrations of 13th century Costume & Soldiers