Manuel Mamikonian was the real leader of Armenia after the death of Varazdat.
The Mamikonian family had long been the leading generals of Armenia, holding the title of Sparapet, basically a chief general.
Manuel had served in the Kushan War in the troops of the Persian king.
His brother Musel Mamikonian had been slain by Varazdat and Manuel had come to be sparapet in his place.
In 378 Varazdat and Manuel had become so mad at each other that they went to war. Manuel prevailed and afterward became the ruler of Iran.
According to Faustus of Byzantium Manuel was convinced that the Persian ruler was plotting against him and so attacked the Persian emissary Suren and his 10,000 troops. Manuel decimated Suren's army but allowed Suren to live and leave.
This led to an invasion of Armenia by the Persian forces. Armies under generals such as Varaz were sent to invade Armenia but were defeated by Manuel. According to Pawstos this led to seven years of peace for Armenia.
Manuel died in 385.[1]