Lee E. Patterson
In the years between Galerius’ crushing defeat of the Persian king Narses in 298 and the resumption of Sasanian hostility toward the Romans by Shapur II in 338, the latter king made diplomatic overtures to Constantine (Lib. Or. 59.67), perhaps around 324 (Barnes 1985: 132, G. Fowden 1994: 148). The emperor’s response is recorded by Eusebius (VC 4.9-13), who claimed to be translating into Greek a letter handwritten in Latin by Constantine himself. Although the authenicity of this letter, in which Constantine claimed to be the protector of Christians everywhere, including those living in Sasanian lands, is routinely questioned by scholars, we have good reason to accept that such a letter was sent and that Eusebius’ version is essentially reliable. What has been lacking in most assessments is a sufficient appreciation for the role Armenia played in Constantine’s eastern policy, which consequently goes a long way to explaining the context of the letter. Constantine’s conversion to Christianity not only furthered his goal of bringing stability and order to the empire (thus interlocking the religious and the political in a way not dissimilar to that of his pagan predecessors: Cameron and Hall 1999: 43-44), but it provided a justification for the expansion of the Roman imperium, now to be a Christian empire ruled by Constantine as appointed by God (so the claim went). Armenia’s official conversion to Christianity in 314 is the key to understanding the country’s role in Constantine’s designs. It is clear that when Constantine made plans to attack the Persians in 337, he envisioned a religious crusade as much as a traditional eastern campaign, with the inclusion of bishops and a tent to serve as a church (Eus. VC 4.57).
Since the first century BCE, Armenia had been vital to Roman interests along the Eastern frontier. Roman policy usually called for Armenia to be a vassal state (the exception lying with Trajan, who reduced it to a province), with the Armenian king expected to enforce Roman policy in the East and support imperial invasions of Persian territory. But with the conversion of Tiridates IV in 314, a new dynamic came into play that had not informed the policies of previous emperors. Christianity would provide a bond that for Constantine would run deeper than the usual geopolitical alignment with Armenia. In fact, the Armenian sources suggest a treaty with Tiridates sometime after the conversion (Aa 877, Faustus 3.21, Elishe p. 72). While we have no specifics about the circumstances and the alliance is not attested in any classical source, we can reasonably put forward Armenia’s traditional role as supporter of eastern campaigns in Constantine’s schema (contra Honigman 1953: 20, who links the alliance to Constantine’s rivalry with Licinius).
Another clue to support this interpretation comes after the death of Tiridates, probably around 330. The classical and Armenian sources are notoriously bad at shedding sufficient light on the events that follow, but Hewsen 1978-1979: 109-111 has argued convincingly for a chaotic period in which various constituencies vied for control of Armenia. Shapur apparently tried to capitalize on the situation by invading and installing a new king in 336 (Moses 3.9, cf. Faustus 3.7). Constantine sought to recover the situation by appointing his own client king. Here, too, he broke new ground. Instead of a native Armenian or other eastern dynast, he appointed a member of the imperial family, his nephew Hannibalianus. His title “king of kings,” as attested in coinage and in the Anonymous Valesianus (6.35, cf. Aur. Vict. Epit. 41.20, Chron. Pasch. p. 532, 1-3), suggests that Constantine was not appointing a governor, as Trajan had done. Armenia was to be a client state with a Roman ruler, someone deemed reliable enough to help the emperor’s efforts not only to neutralize the Sasanian threat but to fulfill his dream of a Christian empire spanning the known world.