Ambrose retires to Milan (residence of Theodosius I) and refuses to celebrate a mass in the emperor's presence, until he repents for ordering the massacre in Thessalonica. Theodosius, filled with remorse, kneels in humility and strips off his royal purple, before the altar of the cathedral in Milan, humbling himself before the church.
A Rouran chief named Heduohan (曷多汗) is defeated and killed in battle against the Toba Northern Wei Dynasty. Surviving Rouran move west towards the Gaoche, led by Heduohan's son and successor, Shelun.
Patriarch Theophilus destroys all pagan temples in Alexandria under orders from Theodosius I. Christians go on an iconoclastic rampage, smashing religious symbols or monuments through the city and destroying the Temple of Serapis. The "Order of Monks" known as the Parabalani take charge of patrolling the streets.
August 22 – Arbogast nominates Eugenius, Roman teacher of rhetoric, as the next emperor of the Western Roman Empire. He sends ambassadors to Theodosius's court asking for his recognition.
Theodosius I becomes the last emperor who rules the whole Roman Empire. He issues an edict reinforcing the prohibition of prayers or sacrifices at non-Christian temples, leading to the persecution of pagans and the end of the almost 2,000-year-old Eleusinian Mysteries. He also bans items of spiritual significance that could be used in the home, such as incense or spiritual figures.
Theodosius I demands the destruction of pagan temples, holy sites, and ancient objects throughout the Roman Empire.
Theodosius I abolishes the Greek Olympic Games, ending a thousand years of festivals, as part of the general Christian policy to establish universal Christian worship in accordance with the doctrines set forth in the Nicene Creed (the next Olympic Games will not be held until 1896).
Winter – The Huns cross the frozen Danube and destroy the villages built by the Goths. Theodosius I, six hundred miles away in Italy, sends no reinforcements to defend the northern frontier.
Alaric, Visigothic leader of the foederati, renounces Roman fealty and is declared king, waging war against both parts of the Roman Empire, and ending a 16-year period of peace.
Alaric besieges Constantinople. After commitments from Rufinus, the Pretorian prefect of the East, and chief adviser to Arcadius, the Goths move further west.
Stilicho arrives in the fall with his army to fight the Goths. Rufinus, the strong man of the east, persuades the emperor to cancel Stilicho's campaign. Emperor Arcadius forbite Stilicho to attack Alaric and demandes that his army leave the territory of the East Roman Empire.
The Huns begin their large-scale attack on the Eastern Roman Empire. They invade Armenia, Cappadocia, and enter parts of Syria, threatening Antioch.[6]
Revolt of Alaric I: Stilicho traps the Visigoths under King Alaric in the Peloponnese, but decides to abandon the campaign against the Visigoths in Greece, thus allowing King Alaric to escape north to Epirus with his loot. Presumably, Stilicho has left Greece in order to prepare for military action in northern Africa, where a rebellion (see Gildonic Revolt in 398) seems imminent.[7]
Emperor Honorius passes a law making barbarian styles of dress illegal in the city of Rome. As a result of this law, everybody in Rome is forbidden from wearing boots, trousers, animal skins, and long hair. This law is passed in response to the increasing popularity of barbarian fashions among the people of Rome.[8][9]
Revolt of Alaric I: After Stilicho returned to Italy, the Eastern Roman Empire concludes a peace treaty with Alaric. The Visigoths are given a settlement area in Illyricum and their king is appointed magister militum per Illyricum.
Gildonic Revolt: Gildo, a Berber serving as a high-ranking official (comes) in Mauretania, rebels against the Western Roman Empire. The Gildonic Revolt is instigated by a powerful official in the Eastern Roman Empire named Eutropius, who wishes to undermine his enemies in the Western Roman Empire by cutting off the grain supply to Rome.[10] After Gildo takes much of North Africa and cuts off the grain supply to Rome, Flavius Stilicho returns to Italy to raise troops against the rebels. After a short campaign in the desert, he defeats Gildo. Gildo flees and commits suicide by hanging himself.
An imperial edict obliges Roman landowners with plantations to yield 1/3 of their fields to the "barbarians" who have been settled in the Roman Empire.
The Emperor Honorius of the Western Roman Empire, who is only 15 years old, closes the gladiatorial schools in Rome, and legally ends munera (gladiator games).
November 26 – Pope Siricius dies at Rome after a 15-year reign in which he has commanded celibacy for priests, asserted papal authority over the entire Western Church, and threatened to impose sanctions on those who do not follow his dictates.
Anastasius I succeeds Siricius as the 39th pope. He seeks to reconcile the churches of Rome and Antioch. Anastasius also condemns the doctrine of Origen.
^Burrell, Emma (2004). "A Re-Examination of Why Stilicho Abandoned His Pursuit of Alaric in 397". Historia: Zeitschrift für Alte Geschichte. 53 (2): 251–256. JSTOR4436726.
^Elton, Hugh (1996). "Fravitta and Barbarian Career Opportunities in Constantinople". Medieval Prosopography. 17 (1): 95–106. ISSN0198-9405. JSTOR44946209.
^Charles, Michael (2005). "Transporting the Troops in Late Antiquity: Naves Onerariae, Claudian and the Gildonic War". The Classical Journal. 100 (3): 275–299. ISSN0009-8353. JSTOR4133022.