Christian tradition states that he was a wealthy Roman army officer who was martyred in Armenia, under Valerian. So these sketches illustrate Armenian costumes from before the Armenian conversion to Christianity (in 301 AD) but definitely with the Christian culture already present in the region. At the time Armenia must have been a place of many coexisting religions. From the Armenian paganism, Roman cults, Persian Zoroastrianism and the growing Christian population. See the sketches bellow:
Sketches of Ancient Armenian Costumes by Eugène Lacoste (1877-1878)
I recently stumbled upon some interesting sketches of Armenian costumes from the 2nd to 3rd century AD. These sketches by Eugène Lacoste (from 1877-1878) depict ancient Armenian costumes, for usage in theaters for the opera about Saint Polyeuctus. Polyeuctus according Christian tradition was an ancient Roman saint who lived in the early 3rd century AD.