380s

Below are some of the important events that happened between 380 and 389.
380
January or February - Emperor Theodosius I is baptized.
February 27 - Edict of Thessalonica: Theodosius I, with co-emperors Gratian and Valentinian II, say that all Roman citizens should become Christians.
The Rock of Cashel is built in Ireland.
The Visigothic chieftain Fritigern dies. His rival Athanaric becomes king of the entire Gothic nation.
Births
Aelia Eudoxia, empress and wife of Arcadius
Alexius, Eastern saint
Eucherius, bishop of Lyon
Hephaistio of Thebes, Egyptian astrologer
Deaths
Peter II, Patriarch of Alexandria
Samudragupta, ruler of the Gupta Empire
Wang Fahui, empress of the Jin Dynasty
381
Roman Emperor Gratian moves the capital to Mediolanum (modern Milan).
The Visigothic chieftain Athanaric becomes the first foreign king to visit the East Roman capital of Constantinople.
Flavian succeeds Meletius as Patriarch of Antioch.
Timothy succeeds Peter as Patriarch of Alexandria.
Births
Helian Bobo, emperor of the Chinese Xiongnu state Xia
Deaths
Athanaric, king of the Visigoths
382
Roman Emperor Gratian removes the Altar of Victory from the Senate.
Births
Jin Andi, emperor of the Eastern Jin Dynasty
Sima Yuanxian, regent during the Jin Dynasty
383
Niall of the Nine Hostages becomes the first High King of Ireland.
Hadrian's Wall is overrun by the Picts.
January 19 - Arcadius becomes Roman Emperor.
Roman troops in Britain call Magnus Maximus Emperor. He crosses over to the continent and makes Trier his capital.
King Ardashir II dies after a 4-year reign. He is succeeded by his son Shapur III.
Births
Lupus of Troyes, French bishop and saint
Deaths
August 25 - Gratian, Roman Emperor
December 10 - Pope Damasus I
Frumentius, the "Apostle to Ethiopia"
384
Magnus Maximus returns to Britain to help them with the Barbarians raids.
An edict of Theodosius I closes pagan temples in the Nile Valley.
King Shapur III signs a treaty with Theodosius I. Armenia is divided in two kingdoms.
December 17 - Pope Siricius succeeds Damasus I as the 38th pope.
Births
September 9 - Honorius, Roman Emperor
Chu Lingyuan, last empress of the Jin Dynasty
Maria, empress and daughter of Stilicho
Sengzhao, Chinese Buddhist
Wang Shen'ai, empress of the Jin Dynasty
Deaths
December 11 - Pope Damasus I
Chu Suanzi, empress of the Jin Dynasty
Geungusu, king of Baekje
Murong Hong, founder of the Xianbei state Western Yan
385
Jinsa of Baekje becomes the 16th king of the ancient Korean kingdom of Baekje.
Copper extraction and casting begins in the mines of Kansanshi in southernmost Africa.
Ammianus Marcellinus begins writing a history covering the years 96 to 378.
The Serapeum in Alexandria is destroyed.
Aurelios Zopyros becomes the last reported athlete at the Ancient Olympic Games.
Births
Avitus, Western Roman Emperor
Murong Chao, emperor of the Xianbei state Southern Yan
Murong Xi, emperor of the Xianbei state Later Yan
Saint Patrick, missionary in Ireland
Paulus Orosius, historian and theologian
Xie Lingyun, Chinese poet of the Southern and Northern Dynasties
Deaths
Aelia Flaccilla, Roman empress and wife of Theodosius I
Chimnyu, king of Baekje (Korea)
Dao An, Buddhist monk of the Jin Dynasty
Fu Jian, emperor of the Chinese Di state Former Qin
Murong Wei, emperor of the Xianbei state Former Yan
386
The Greuthungi cross the Danube to raid the Roman garrisons.
Magnus Maximus invades Italy.
The Northern Wei Dynasty begins in China.
Births
Jin Gongdi, last emperor of the Jin Dynasty
Nestorius, founder of Nestorianism
Deaths
Cyril of Jerusalem, theologian and saint
Duan Sui, ruler of the Western Yan
Fu Pi, emperor of the Former Qin
Jin Feidi, emperor of the Jin Dynasty
Murong Chong, emperor of the Western Yan
Murong Yao, emperor of the Western Yan
Murong Yi, ruler of the Western Yan
Murong Zhong, emperor of the Western Yan
387
Spring - Emperor Theodosius I increases the taxes in Antioch. The peasants start a riot.
Magnus Maximus invades Italy. Emperor Valentinian II, age 16, is forced out of Rome.
Winter - Emperor Theodosius I takes Valentinian II into protection.
Deaths
Aelia Flaccilla, wife of Theodosius I
Alatheus, chieftain of the Ostrogoths
Saint Monica, mother of Augustine of Hippo
388
Battle of the Save: Emperor Theodosius I defeats Magnus Maximus near Emona.
Valentinian II is restored as Roman Emperor.
August 28 - Magnus Maximus surrenders at Aquileia and is executed.
Bahram IV becomes the twelfth Sassanid king of Persia.
Emperor Chandragupta II, ruler of the Gupta Empire, begins a war against the Shaka Dynasty in West India.
Births
Yao Hong, emperor of the Chinese Qiang state Later Qin
Deaths
Flavius Victor, son of Magnus Maximus and co-emperor
Qifu Guoren, ruler of the Xianbei state Western Qin
Shapur III, king of the Sassanid Empire
389
All pagan buildings in Alexandria are destroyed by fire. This includes the library.