Greek becomes an official language in the Eastern Roman Empire in 439.

Theodoret, bishop of Cyrrhus (Syria) from 423, has converted more than one thousand Marcionites in his diocese.

Yazdegerd II moves his court to Khorasan in the beginning of his reign to face the threat from the White Huns.

This results in Yazdegerd gaining control of Bactria, which secures the eastern flank of the Sassanid Empire.

Hun and Roman envoys meet at Margum (modern Bosnia and Herzegovina), an important market town on the Sava River.

After negotiations, Attila and his brother Bleda who are present, accept a four-point peace plan.

Trading rights between the two states are confirmed and emperor Theodosius II pays an annual tribute of seven hundred pounds of gold.

Aetius, after checking the Visigoths at Toulouse between 437 and 439, returns to Italy in 440.

Aëtius had refused Theodoric's offer of peace, but the king wins the decisive battle at before the walls of Tolosa.

Litorius, who dies in Gothic imprisonment from the injuries which he had received in the battle, is noted for being the last Roman commander in the ancient Roman military history to perform pagan rites and consult auspices before a battle.

Avitus becomes Praetorian prefect of Gaul in 439; in this same year, according to the orders of Aëtius, Avitus goes to Tolosa and offers a peace treaty, which Theodoric accepts, having suffered heavy losses in the battle.

Here, Avitus meets the son of Theodoric who will later become King Theodoric II.

Avitus inspires the young Theodoric to study Latin poets.

Romans perhaps recognize the sovereignty of the Visigoth state at this time.

The Visigoths obtain access to the Mediterranean Sea and the roads to the Pyrenees.

Suevic king Rechila, invading southern Iberia, takes the provincial capital of Mérida in 439.

Ambrosius Aurelianus, num, the leader of a combined force of Romano-British forces from across southern Britain, according to Historia Britto, defeats the Anglo-Saxons under one Vitalinus (possibly Vortigern) in the Battle of Guoloph, at present Over Wallop.

He is given all the kingdoms of the western side of Britain.

Ambrosius Aurelianus is one of the few people that Gildas identifies by name in his sermon De Excidio et Conquestu Britanniae, and the only one named from the fifth century.

The Vandals invade the province of Africa Proconsularis in a surprise move, capturing Carthage on October 19 without a fight; the Vandals enter the city while most of the inhabitants are attending the races at the hippodrome.

They take the rest of the province of Africa, then establish an independent autocracy under Genseric.

The Vandals establish a North African granary that enables them to enforce their will on other nations who are dependent on North Africa for grain and other food staples; the Vandals use Carthage as a base from which to raid Sicily and southern Italy.

The Huns under Attila, reappearing in force along the frontier of the Western Roman Empire, attack merchants on the north bank of the Danube and cities in Illyricum, including (according to Priscus) Viminacium, a city of Moesia.