Europe 346: Nisibis War
In 336, shortly before the death of Constantine I, Shah Shapur II had launched an offensive to restore Sasanian Persian rule in Armenia and seize the important eastern Roman cities of Nisibis and Singara. The war continued intermittently through the 340s, with Constantius II now in charge of the eastern Roman forces, but would enter a period of stalemate in the early 350s when both parties decided that they had more pressing issues on other fronts.
6 Jan–? ?? 341 Dedication Council of Antioch▲
In 341 Constantius II and ninety-seven Eastern bishops—but not the Bishop of Rome—attended the dedication of the Domus Aurea, the great church of Antioch. They then held a council which attempted to find a compromise between Arianism, which was strong in the East, and the Nicene Creed by avoiding the term homoousios (used to describe Jesus and God as being of the same essence). This attempt was derided as simple Arianism, or ‘Semi-Arianism’, by its more orthodox opponents, but gained a following due to its support by Constantius.
341–342 Constans’ Frankish War▲
In 341 Constans traveled to Gaul to establish his authority over the officers of his late brother Constantine II. Later that year he led a campaign against the Franks, achieving a significant victory over them in 342. Following this, in the winter of 342/343 he briefly crossed over to Britain, probably to conduct a campaign there too.
342 Bosporan decline▲
In the mid-3rd Century, after over a century of facing barbarian attacks and diminishing trade, the Bosporan Kingdom appears to have fallen irreversibly into decline. The last coins ascribed to a Bosporan king—that of Rhescuporis VI—were minted in 341/342 and no further rulers are known except for one Douptounos, who made an inscription on a tower at some point between 383 and 522. It remains uncertain as to whether the kingdom fell to the Huns in the late 4th century or lasted until the region was annexed by Justinian in the 530s.
343 Council of Serdica▲
In 343, at the request of Pope Julius I, the western Roman emperor Constans and the eastern Roman emperor Constantius II convened a synod at Serdica, which was attended by 170 bishops. The council restored the bishops Athanasius of Alexandria and Paul I of Constantinople—who had been expelled by the Arians in 340 and 341 respectively—and rejected any revision of the Nicene Creed. These efforts failed to stem the rift forming between the Nicene-dominated Western Church and the Arian-dominated Eastern Church.
343 Constantius II’s Adiabene Campaign▲
In 343, or possibly 344, Constantius II crossed the Tigris into Persia and captured a small city. As a result he was awarded the title Adiabenicus.
344 Battle of Singara▲
In the late spring or early summer of 344 Shapur II led a Persian army into Roman Mesopotamia to besiege Singara but was soon met by Constantius II and the Roman army. The Romans pursued Shapur as he withdrew towards the Tigris and, after defeating the Persians in battle, sacked their camp that evening. However, the discipline of the legions soon broke down as, stricken with thirst from the day’s march, they gorged themselves on the Persian water supplies. Seizing this opportunity, Persian archers fired on the massed Romans, inflicting heavy casualties and allowing Shapur and the remnants of his army to escape across the Tigris.
346 Shapur II’s Second Siege of Nisibis▲
In 346 Shah Shapur II of the Sasanian Persian Empire invaded the Roman Empire and again besieged Nisibis. Despite being in Antioch at the time, Constantius II did not attempt to intervene. Nonetheless, after seventy-eight days without success, Shapur abandoned the siege and withdrew.