Events in Armenia apparently occupy the attention of Ardashir II during his four-year reign.

Arsaces's son Pap had been murdered during Shapur's reign and the Romans had replaced him with a certain Varaztad, who was a distant member of the Arsacid family.

However, real power was in the hands of one Moushegh Mamikonian, apparently a noble in the Armenian court.

Moushegh, suspected of having conspired with the Emperor of Rome, had later been murdered by Varazdat.

This act had roused the indignation of Moushegh's brother Manuel, who had rebelled against Varazdat and with the support of Persia deposed him and placed upon the Armenian throne Zermandueht, the widow of Pap, who had then made Manuel the Sparapet or Commander-in-chief.

In return for their services, Manuel had allowed the Persians to maintain a garrison in Armenia, but this arrangement did not work for long.

A nobleman named Meroujan had incorrectly informed Manuel that the commandant of the Persian garrison desired to capture him.

Enraged, Manuel had fallen upon the ten thousand Persian soldiers stationed in Armenia and murdered them, but Manuel died soon afterwards and confusion followed.

Ardashir and the Roman Emperor Theodosius, desiring to maintain peace in the borderlands, had decided upon a treaty, but Ardashir died in 383 before the treaty could be signed; his son Shapur III had eventually signed and ratified the treaty in the year 384, resulting in the splitting of the kingdom between the Roman and the Sassanid empires three years later.