The Arsacids
Both Rome and Parthia strove to establish their own candidates on the Armenian throne until a lasting measure of equilibrium was secured by the treaty of Rhandeia, concluded in 63 ce between the Roman general Gnaeus Domitius Corbulo and Tiridates (Trdat), brother of the Parthian king Vologeses I. Under this treaty a son of the Parthian Arsacid dynasty, the first being Tiridates, would occupy the throne of Armenia but as a Roman vassal. A dispute with Parthia led to Armenia’s annexation by the Roman emperor Trajan in 115 or 116, but his successor, Hadrian, withdrew the frontier of the Roman Empire to the Euphrates. After the Roman emperor Caracalla’s capture of King Vagharshak and his attempt to annex the country in 216, his successor, Macrinus, recognized Vagharshak’s son Tiridates II (Khosrow the Great in Armenian sources) as king of Armenia (217).
Tiridates II’s resistance to the Sāsānid dynasty after the fall of the Arsacid dynasty in Persia (224) ended in his assassination by their agent Anak the Parthian (c. 238) and in the conquest of Armenia by Shāpūr I, who placed his vassal Artavazd on the throne (252). Under Diocletian, the Persians were forced to relinquish Armenia, and Tiridates III, the son of Tiridates II, was restored to the throne under Roman protection (c. 287); his reign determined the course of much of Armenia’s subsequent history, and his conversion by St. Gregory the Illuminator and the adoption of Christianity as the state religion (c. 314) created a permanent gulf between Armenia and Persia. The Armenian patriarchate became one of the surest stays of the Arsacid monarchy and the guardian of national unity after its fall. The chiefs of Armenian clans, called nakharars, held great power in Armenia, limiting and threatening the influence of the king.
The dissatisfaction of the nakharars with Arshak II led to the division of Armenia into two sections, Byzantine Armenia and Persarmenia (c. 390). The former, comprising about one-fifth of Armenia, was rapidly absorbed into the Byzantine state, to which the Armenians came to contribute many emperors and generals. Persarmenia continued to be ruled by an Arsacid in Dvin, the capital after the reign of Khosrow II (330–339), until the deposition of Artashes IV and his replacement by a Persian marzpān (governor) at the request of the nakharars (428). Although the Armenian nobles had thus destroyed their country’s sovereignty, a sense of national unity was furthered by the development of an Armenian alphabet and a national Christian literature; culturally, if not politically, the 5th century was a golden age. (See Armenian literature.)
The marzpāns
The Persians were not as successful as the Byzantines in their efforts to assimilate the strongly individualistic Armenian people. The misguided attempt of the Persian Sāsānian king Yazdegerd II to impose the Zoroastrian religion upon his Armenian subjects led to war in 451. The Armenian commander St. Vardan Mamikonian and his companions were slain at the Battle of Avarayr (June 2?, 451), but the Persians renounced their plans to convert Armenia by force and deposed their marzpān Vasak of Siuniq, the archtraitor of Armenian tradition.
The revolt of 481–484, led by Vahan Mamikonian, Vardan’s nephew, secured religious and political freedom for Armenia in return for military aid to Persia, and with the appointment of Vahan as marzpān the Armenians were again largely the arbiters of their own affairs. Their independence was further asserted in 554, when the second Council of Dvin rejected the dyophysite formula of the Council of Chalcedon (451), a decisive step that cut them off from the West as surely as they were already ideologically severed from the East. (According to the dyophysite formula, Christ, the Son of God, consists of two natures, “without confusion, without change, without separation, without division.”)
In 536 the Byzantine emperor Justinian I reorganized Byzantine Armenia into four provinces, and, by suppressing the power of the Armenian nobles and by transferring population, he completed the work of Hellenizing the country. In 591 its territory was extended eastward by the emperor Maurice as the price of helping the Sāsānian king Khosrow II regain the Persian throne. After transporting many Armenians to Thrace, Maurice (according to the Armenian historian Sebeos) advised the Persian king to follow his example and to send “this perverse and unruly nation, which stirs up trouble between us,” to fight on his eastern front. During the war between the emperor Phocas and Khosrow, the Persians occupied Byzantine Armenia and appointed a series of marzpāns, only to be ousted by the emperor Heraclius in 623. In 628, after the fall of Khosrow, the Persians appointed an Armenian noble, Varaztirotz Bagratuni, as governor. He quickly brought Armenia under Byzantine rule but was exiled for plotting against Heraclius (635).