Goguryeo's expansion meets temporary setbacks when in…

Constans defends his realm successfully against the Franks in 341 and 342.

Gao Zhao offers a tribute in 343 and offers to be a vassal.

Murong Huang returns his father's body but keeps his mother as hostage.

Bishop Hosius, who had been the ecclesiastical advisor to the late Constantine I, presides in the winter of 342-343 at the Council of Serdica (modern Sofia), which city had reached its greatest height under Constantine.

The council, called by Constans to settle the conflict between the orthodox Bishop Athanasius of Alexandria and the Arian Paul of Constantinople, achieves little, being boycotted by the Eastern bishops because the Westerners and the Egyptians insist on the presence of Athanasius the great defender of Trinitarian Christianity and the principal opponent of Arianism.

The Council of Philippopolis (held in 343, 344, or 347) is a result of Arian bishops from the Eastern Roman Empire leaving the Council of Sardica to form their own counter council.

In Philippopolis, they anathematize the term homoousios, in effect excommunicating Pope Julius as well as their rivals at the Council in Sardica, and introduce the term Anomoian.

As a result, the Arian controversy is perpetuated, rather than resolved, as had been the original intention of the emperors Constans and Constantius together with Julius, who had called the Council of Sardica.

A visit by Constans to Britain in the early months of 343 will turn out to be the last made by a legitimate emperor.

The speed of his trip, paired with the fact he had crossed the English Channel during the dangerous winter months, suggests it was in response to a military emergency of some kind, possibly to repel the Picts and Scots.

Shapur II, Sassanid ruler of the Persian Empire, has waged his campaign against Constantius II from 337, but it has so far been mostly unsuccessful.

Shapur had repelled Constantius’s invasion of Adiabene (Mesopotamia) in 343 but is unable to take the fortress of Singara in the siege of 344).

Chinese records first describe the Korean polity of Baekje as a kingdom in 345.

One source estimates three thousand monasteries dotting Egypt from north to south by the time of the death in 345 of Pachomius, the founder of cenobitic monasticism.

This number will grow within a generation after his death to seven thousand, then expand from Egypt into Palestine and the Judea Desert, Syria, North Africa and eventually Western Europe.

The emperor Constans, an ardent orthodox Christian, is known as a vigorous opponent of Arianism and paganism and a supporter of Athanasius, the Bishop of Alexandria.

Constans in 341 promulgates an edict banning pagan sacrifices and magic rituals under penalty of death.

In the contrast between the Nicene and Arian factions, Constans supports the former, while Constantius the latter.

Constans wins acceptance for a religious policy favorable to the Nicaeans, and secures the return of their leader, Athanasius, to Egypt, where the Alexandrians welcome him as a popular hero.

Ulfilas has worked for seven years among the Goths north of the Danube.

Because of persecution by the pagan ruler of the Thervings, he leads his congregation to …