Toward the close of the Fifth Century, Yezdegerd II., the king of Persia, "attempted, with the intention of assimilating Armenia entirely, to convert her by force to Zoroastrianism. The Armenians, led by Vartan Mamigonian, Catholicos Hovsep, and the entire clergy, revolted with one accord. Yezdegerd hurled upon Armenia a formidable army, in order to crush the Armenian resistance. Vartan and his seventy thousand companions in arms faced the enormous Persian hosts in the memorable battle of Avarair. Vartan fell in the struggle, his troops were scattered, and Armenia found herself at the mercy of the ferocious Persian soldiers. But spirit triumphed over brute force; the entire people, entrenched in the fortresses and in the passes of the Armenian mountains, continued an incessant guerilla war