Valens in the context of "Gothic War (376–382)"

Theodosius I (Ancient Greek: Θεοδόσιος Theodosios; 11 January 347 – 17 January 395), also known as Theodosius the Great, was Roman emperor from 379 to 395. He won two civil wars and was instrumental in establishing the Nicene Creed as the orthodox doctrine for Nicene Christianity. Theodosius was the last emperor to rule the entire Roman Empire before its administration was permanently split between the Western Roman Empire and the Eastern Roman Empire. He ended the Gothic War (376–382), but did so on terms disadvantageous to the empire, with the Goths remaining and politically autonomous within Roman territory, albeit as nominal allies.

Born in Hispania, Theodosius was the son of a high-ranking general of the same name, Theodosius the Elder, under whose guidance he rose through the ranks of the Roman army. Theodosius held independent command in Moesia in 374, where he had some success against the invading Sarmatians. Not long afterwards, he was forced into retirement, and his father was executed under obscure circumstances. Theodosius soon regained his position following a series of intrigues and executions at Emperor Gratian's court. In 379, after the eastern Roman emperor Valens was killed at the Battle of Adrianople against the Goths, Gratian appointed Theodosius as a successor with orders to take charge of the military emergency. The new emperor's resources and depleted armies were not sufficient to drive the invaders out; in 382 the Goths were allowed to settle south of the Danube as autonomous allies of the empire. In 386, Theodosius signed a treaty with the Sasanian Empire which partitioned the long-disputed Kingdom of Armenia and secured a durable peace between the two powers.

The Imperial Library of Constantinople, in the capital city of the Byzantine Empire, was the last of the great libraries of the ancient world. Long after the destruction of the Great Library of Alexandria and the other ancient libraries, it preserved the knowledge of the ancient Greeks and Romans for almost 1,000 years. A series of unintentional fires over the years and wartime damage, including the raids of the Fourth Crusade in 1204, impacted the building and its contents. While there were many reports of texts surviving into the Ottoman era, no substantive portion of the library has ever been recovered. The library was founded by Constantius II (reigned 337–361 AD), who established a scriptorium so that the surviving works of Greek literature could be copied for preservation. The Emperor Valens in 372 employed four Greek and three Latin scribes. The majority of Greek classics known today are known through Byzantine copies originating from the Imperial Library of Constantinople.

Niš (/ˈniːʃ/; Serbian Cyrillic: Ниш, Serbian pronunciation: [nîːʃ] ; names in other languages), less often spelled in English as Nish, is the third largest city in Serbia and the administrative center of the Nišava District. It is located in the southern part of Serbia. According to the 2022 census, the city proper has a population of 178,976, while its administrative area has a population of 249,501 inhabitants.

Several Roman emperors were born in Niš or used it as a residence: Constantine the Great, the first Christian emperor and the founder of Constantinople, Constantius III, Constans, Vetranio, Julian, Valentinian I, Valens; and Justin I. Emperor Claudius Gothicus decisively defeated the Goths at the Battle of Naissus (present-day Niš). Later playing a prominent role in the history of the Byzantine Empire, the city's past would earn it the nickname Imperial City.

Gratian (/ˈɡreɪʃiən/; Latin: Gratianus; 18 April 359 – 25 August 383) was emperor of the Western Roman Empire from 367 to 383. The eldest son of Valentinian I, Gratian was raised to the rank of Augustus as a child and inherited the West after his father's death in 375. He nominally shared the government with his infant half-brother Valentinian II, who was also acclaimed emperor in Pannonia on Valentinian's death. The East was ruled by his uncle Valens, who was later succeeded by Theodosius I.

Gratian subsequently led a campaign across the Rhine, attacked the Lentienses, and forced the tribe to surrender. That same year, the eastern emperor Valens was killed fighting the Goths at the Battle of Adrianople, which led to Gratian elevating Theodosius to replace him in 379. Gratian favoured Nicene Christianity over traditional Roman religion, issuing the Edict of Thessalonica, refusing the office of pontifex maximus, and removing the Altar of Victory from the Roman Senate's Curia Julia. The city of Cularo on the Isère river in Roman Gaul was renamed Gratianopolis after him, which later evolved to Grenoble. By 383 Gratian had become unpopular with his army, which abandoned him during a confrontation with the usurper Magnus Maximus near Lutetia (Paris). Gratian fled to Lugdunum and was later murdered.

The Battle of Adrianople also known as Battle of Hadrianopolis was fought between the Eastern Roman army led by the Roman emperor Valens and Gothic rebels (largely Thervings as well as Greutungs, non-Gothic Alans, and various local rebels) led by Fritigern. The battle took place on 9 August 378 in the vicinity of Adrianople, in the Roman province of Thracia (modern Edirne in European Turkey). It ended with an overwhelming victory for the Goths and the death of Emperor Valens.

As part of the Gothic War of 376–382, the battle is often considered the start of the events which led to the fall of the Western Roman Empire in the 5th century.

Ammianus Marcellinus, occasionally anglicized as Ammian (Greek: Αμμιανός Μαρκελλίνος; born c. 330, died c. 391 – 400), was a Greek and Roman soldier and historian who wrote the penultimate major historical account surviving from antiquity (preceding Procopius). Written in Latin and known as the Res gestae, his work chronicled the history of Rome from the accession of Emperor Nerva in 96 to the death of Valens at the Battle of Adrianople in 378. Only the sections covering the period 353 to 378 survive.

The Valentinian dynasty, commonly known as the Valentinianic dynasty, was a ruling house of five generations of dynasts, including five Roman emperors during late antiquity, lasting nearly a hundred years from the mid fourth to the mid fifth century. They succeeded the Constantinian dynasty (r. 306–363) and reigned over the Roman Empire from 364 to 392 and from 425 to 455, with an interregnum (392–425), during which the Theodosian dynasty ruled and eventually succeeded them. The Theodosians, who intermarried into the Valentinian house, ruled concurrently in the east after 379.

The Valentinian dynasty's patriarch was Gratianus Funarius, whose sons Valentinian I and Valens were both made Roman emperors in 364. Valentinian I's two sons, Gratian and Valentinian II both became emperors. Valentinian I's daughter Galla married Theodosius the Great, the emperor of the eastern empire, who with his descendants formed the Theodosian dynasty (r. 379–457). In turn, their daughter, Galla Placidia married a later emperor, Constantius III (r. 421–421). Their son, Valentinian III (r. 425–455), who ruled in the west, was the last emperor of the dynasty, whose death marked the end of dynasties in the western empire. During the interregnum, Theodosius' son Honorius ruled in the west, and concurrently with Constantius III in 421. The dynasty has been labelled as Pannonian, based on the family origin in Pannonia Secunda in the western Balkans.

Oribasius or Oreibasius (Greek: Ὀρειβάσιος or Ὀριβάσιος; c. 320 – 403) was a Greek medical writer and the personal physician of the Roman emperor Julian. He studied at Alexandria under physician Zeno of Cyprus before joining Julian's retinue. He was involved in Julian's coronation in 361, and remained with the emperor until Julian's death in 363. In the wake of this event, Oribasius was banished to foreign courts for a time, but was later recalled by the emperor Valens.

Valentinian I (Latin: Valentinianus; 321 – 17 November 375), sometimes known as Valentinian the Great, was Roman emperor from 364 to 375. He ruled the Western half of the empire, while his brother Valens ruled the East. During his reign, he fought successfully against the Alamanni, Quadi, and Sarmatians, strengthening the border fortifications and conducting campaigns across the Rhine and Danube. Also, his general Theodosius the Elder defeated a revolt in Africa and the Great Conspiracy (a coordinated assault on Roman Britain by Picts, Scoti, and Saxons). Valentinian founded the Valentinian dynasty, with his sons Gratian and Valentinian II succeeding him in the western half of the empire and his daughter Galla marrying emperor Theodosius I.