Conflict & Security in the 4th century

236 sourced entries, 300 CE to 399 CE, oldest first. Also see Conflict & Security across every century or everything else in the 4th century.

• 300The Yayoi period ends in Ancient Japan (approximate date).source
• 300Caesar Constantius I wins a victory over the Franks (approximate date).source
• 300Micheon becomes ruler of the Korean kingdom of Goguryeo.source
• 301February 3 – May 30 – Sima Lun briefly usurps the Jin Dynasty.source
• 301Caesar Galerius begins a major war against the Carpi and Bastarnae and wins the first of several victories.source
• 302Emperor Diocletian persecutes the Manichaeans, accusing them of being a Persian fifth column.source
• 302Caesar Galerius wins his second victory over the Carpi.source
• 302An invasion of Gaul by the Alemannic Lingones almost traps Caesar Constantius I between the enemy and the walls of a town. Constantius himself is carried onto the wall via a crane. However, within the same day, Constantius sallies forth from the walls and defeats the enemy in a major battle.source
• 303Galerius wins his third victory over the Carpi and is perhaps joined on campaign by Diocletian. The Arch of Galerius is dedicated in Thessaloniki.source
• 303Caesar Constantius I wins a victory over Germanic invaders in the battle of Vindonissa.source
• 304Caesar Constantius I besieges a Germanic raiding force on an island in the Rhine and forces their surrender.source
• 304Biryu becomes king of the Korean kingdom of Baekje.source
• 304Caesar Galerius, perhaps accompanied by Emperor Diocletian, wins his fourth and final victory over the Carpi. Many of the surviving Carpi and Bastarnae are resettled in the Roman Empire, where they are split up. The Bastarnae are not attested after this time, and the Carpi are attested only once more in the 310s.source
• 305Summer – Constantine joins his father at Bononia (Boulogne) in Gaul; they cross the Channel to Britain and make their way to Eboracum (York), capital of Britannia Secunda and home to a large military base. They campaign with success against the Picts.source
• 305Galerius begins a series of campaigns against the Sarmatians, winning his first victory before the end of the year.source
• 306Winter: Constantine fights with success against the Franks.source
• 306The War of the Eight Princes ends in China.source
• 307Winter: Emperor Galerius wins his second victory over the Sarmatians.source
• 307Galerius sends Valerius Severus with the army of northern Italy, to suppress the rebellion in Rome. However, faced with their former emperor Maximian, the soldiers desert him, and Severus flees to Ravenna. Maximian besieges Severus in Ravenna, who then surrenders. Maxentius makes Severus a hostage, in an attempt to keep Galerius at bay.source
• 308April: In Rome, Emperor Maximian attempts to depose his son Maxentius, but the soldiers in Rome side with Maxentius and force Maximian to flee to the court of Constantine I.source
• 308November 11 – The Conference of Carnuntum: Attempting to keep peace within the Roman Empire, Galerius recalls Diocletian briefly from retirement, and they convene with Maximian. Diocletian persuades Maximian to return to retirement, and he and Galerius declare Maxentius a public enemy. Licinius is proclaimed Augustus of the west, while rival contender Constantine I is again declared Caesar.source
• 308The overthrow of Maximian prompts the soldiers of Roman Africa to prop up the vicarius of Africa, Domitius Alexander, as a usurper.source
• 308The Han-Zhao Dynasty is established in northern China, marking the official inception of the long lasting Uprising of the Five Barbarians.source
• 308Winter: Emperor Galerius wins his third and final victory over the Sarmatians.source
• 309Gaius Ceionius Rufius Volusianus, the Praetorian Prefect of Emperor Maxentius, defeats the usurper Domitius Alexander and purges Africa of his supporters.source
• 310July – Maximian flees to Marseille where he is besieged and surrenders. Constantine encourages his suicide and Maximian, age 60, hangs himself. Emperor Maxentius condemns the killing of his father.source
• 310Maximian, retired emperor, rebels against Constantine I in Arles while the latter is campaigning against the Franks.source
• 310Haelhae becomes the king of the Korean kingdom of Silla.source
• 310Licinius campaigns with success against the Carpi.source
• 311July 13 – Disaster of Yongjia: Xiongnu soldiers led by Liu Cong conquer and pillage the Jin dynasty capital at Luoyang and capture Emperor Huai; 30,000 residents in the city are massacred.source
• 312October 28 – Battle of the Milvian Bridge: Constantine defeats Maxentius at the Milvian Bridge, becoming the only Roman emperor in the West. Prior to the battle, he reportedly has a vision of a cross (labarum) with the phrase "in hoc signo vinces" ("In this sign you shall conquer"). This encourages him to convert to Christianity.source
• 312Constantine forges an alliance with co-emperor Licinius, and offers him his half-sister, Constantia, in marriage. The Praetorian Guard and Imperial Horse Guard (equites singulares Augusti) are disbanded.source
• 312Emperor Maximinus Daza campaigns unsuccessfully against the Armenians.source
• 312Constantine I crosses the Cottian Alps with an army (40,000 men) and defeats Maxentius's generals in three battles at Turin, Brescia and Verona. Maxentius's Praetorian Prefect Ruricius Pompeianus is killed in the fighting outside Verona.source
• 313March 14 – Emperor Huai of Jin is executed by Liu Cong, ruler of the Xiongnu state (Han-Zhao). At the imperial new year he and a number of former Jin officials are poisoned. Crown prince Min of Jin, age 13, succeeds, in Chang'an, his uncle Huai of Jin and becomes the new emperor of the Jin Dynasty.source
• 313Emperor Maximinus Daza crosses the Bosphorus with an army of 70,000 men and lays siege to Heraclea in Thrace. He captures the city after eight days.source
• 313Battle of Tzirallum: Licinius defeats his rival Maximinus in Thrace, who then flees to Cilicia. After losing the Cilician Gates to Licinius' forces, Maximinus commits suicide.source
• 316October 8 – Battle of Cibalae: Constantine the Great defeats his rival Licinius near the town of Colonia Aurelia Cibalae (modern-day Vinkovci, Croatia). Licinius is forced to flee to Sirmium and loses all of the Balkans except for Thrace. Peace negotiations are initiated between the two Augusti, but they are unsuccessful.source
• 316December – Battle of Mardia: Constantine I defeats his rival Licinius and senior officer Valerius Valens, near the town of Harmanli (Bulgaria).source
• 316Han-Zhao forces capture Chang'an, capital of the Chinese Western Jin dynasty. Emperor Min of Jin surrenders to Liu Yao, ending the Western Jin.source
• 316Constantine I sends his half-brother Julius Constantius to Licinius at Sirmium (Pannonia), with the proposal to accept Bassianus as Caesar and give him power over Italy. Licinius refuses, and forces a conspiracy against Constantine.source
• 316Licinius elevates Valerius Valens to Augustus, and mobilises an army against Constantine. Bassianus is accused of conspiracy and executed.source
• 317Sixteen Kingdoms: Jingwen (later Yuan of Jin) flees with remnants of the Jin court and noble families to the south. He succeeds Emperor Min of Jin as first ruler of the Eastern Jin Dynasty and decides to make Jiankang (modern Nanjing) his new capital.source
• 318The Eastern Jin dynasty loses its territories to the north of the Yangtze River, to the benefit of the Xiongnu and the Xianbei. The Former Zhao state is proclaimed; Liu Can and the state ruling family at Pingyang is executed in a coup d'état by Jin Zhun, who is in turn overthrown by Shi Le and Liu Yao.source
• 320Zhang Shi (張寔), Zhang Duke of Xiping and governor of Liang Province, (涼州)is assassinated by Yan She (閻涉) and Zhao Ang (趙卬) and replaced by Zhang Mao (張茂), commonly accepted first ruler of the Chinese state Former Liang.source
• 321Tuoba Heru launches a coup d'état against his cousin Tuoba Yulü and becomes the new Prince of Dai.source
• 323Emperor Constantine the Great defeats the invading Goths and Sarmatians north of the Danube in Dacia, and claims the title of Sarmaticus Maximus.source
• 324July 3 – Battle of Adrianople: Emperor Constantine the Great defeats his rival Licinius near Adrianople, forcing him to retreat to Byzantium. Constantine then invades Thrace with a Visigothic force and raids the countryside.source
• 324July – Battle of the Hellespont: Flavius Julius Crispus, the designated heir of his father Constantine, destroys the naval fleet of Licinius in the Dardanelles, allowing Constantine to cross over the Bosphorus into Asian provinces. Byzantium is besieged and Licinius assembles a second military force, under his newly elevated co-emperor Martinian at Lampsacus (modern-day Lapseki).source
• 324August 9 – (guiyou day of the 7th month of the 2nd year of the Tai'ning era) In Jin dynasty China, the rebel warlord Wang Dun succumbs to illness as the armies of the Emperor Ming of Jin are approaching his camp.source
• 324September 18 – Battle of Chrysopolis: Constantine I definitively defeats Licinius at Chrysopolis, and becomes sole Emperor, thus ending the period of the Tetrarchy. Licinius escapes and gathers around 30,000 of his surviving troops at Nicomedia. Thus, the Civil wars of the Tetrarchy, which began in 306, end with Constantine ruling as sole Emperor.source
• 324Constantine reorganises the Roman army in smaller units classified into three grades: palatini, (imperial escort armies); comitatenses, (forces based in frontier provinces) and limitanei (auxilia border troops).source
• 325Constantine forbids criminals being forced to fight to the death as gladiators.source
• 325Constantine has deposed Emperors Licinius and Martinian executed in Thessalonica and Cappadocia respectively for conspiring and raising troops against him.source
• 329The Han-Zhao dynasty, a Southern Xiongnu state during the Sixteen Kingdoms, ends.source
• 330Ezana, king of Axum, extends his area of control to the west. He defeats the Nobates, and destroys the kingdom of Meroë.source
• 332Emperor Constantine I and his son Constantine II, aged 16, defeat the Goths in Moesia. The Goths become Roman allies and protect the Danube frontier.source
• 333Calocaerus revolts against Constantine I and proclaims himself emperor. Flavius Dalmatius, responsible for the security of the eastern frontier, is sent to Cyprus to suppress the rebellion.source
• 333Shi Hong succeeds his father Shi Le as Emperor of the Later Zhao Empire, in the Period of the Sixteen Kingdoms, but Shi Hong's third cousin Shi Hu holds the real power. Empress Dowager Liu (widow of Shi Le) fails to get rid of Shi Hu, and Shi Hu has her deposed and killed.source
• 333Emperor Constantine the Great pulls Roman troops out of Britain, and abandons work on Hadrian's Wall.source
• 334Flavius Dalmatius puts down a revolt in Cyprus, led by Calocaerus. Calocaerus is brought to Tarsus (Cilicia), and executed.source
• 334The Goths protect the Danube frontier against an invasion by the Vandals.source
• 335Samudragupta succeeds Chandragupta I as king of the Gupta Empire.source
• 335Emperor Shi Hu moves the capital of the Later Zhao state to Yecheng.source
• 337Shapur II besieges the Roman fortress of Nisibis (Syria), but is repulsed by forces under Lucilianus.source
• 337King Shapur II of Persia begins a war against the Roman Empire. He sends his troops across the Tigris to recover Armenia and Mesopotamia.source
• 338The Romans, allied with the Goths, arrive in the north of the Roman Empire to protect the Danube frontier.source
• 338Shapur II, king of the Persian Empire, begins a widespread persecution of Christians. He orders forcible conversions to the state religion, Zoroastrianism, lest the Christians disrupt his realm while he is away fighting the Romans in Armenia and Mesopotamia.source
• 338Emperor Constantius II intervenes against the Persians in Armenia.source
• 339Emperor Constantius II hastens to his territory in the East, where a revived Persia under King Shapur II is attacking Mesopotamia. For the next 11 years, the two powers engage in a war of border skirmishing, with no real victor.source
• 340Constantine II, emperor of the western part of the Roman Empire (Britain, Gaul, the Rhine provinces and Iberia), crosses the Alps and attacks the army of his brother Constans I, emperor of the central part of the Roman Empire (Upper Danube, Italy and middle Africa). They clash at Aquileia in northern Italy. Constantine is killed in a skirmish by an ambush of Constans' troops.source
• 340Constantinople, capital of Emperor Constantius II, becomes the largest city in the world, taking the lead from Rome, capital of his brother Constans I.source
• 340Constans is left sole ruler of the Western part of the Roman Empire, with his other brother, Constantius II, emperor of the Eastern portion.source
• 342Goguryeo is invaded by Murong Huang of the Xianbei.source
• 342Jin Kangdi succeeds his brother Jin Chengdi as emperor of China.source
• 342Emperor Constans I campaigns in Britain against the Picts.source
• 343The Eastern Roman Emperor Constantius II campaigns in Adiabene, a vassal kingdom of Armenia (Persian Empire).source
• 343The Western Roman Emperor Constans I is in Britain, possibly in a military campaign against the Picts and Scots (the last visit to Britain by a legitimate emperor).source
• 344Battle of Singara: The Roman army under Constantius wins a close victory, at the strongly fortified city of Singara (Mesopotamia). His enemy, King Shapur II, is forced to lift the siege, and withdraw the Persian army.source
• 344Jin Mudi, age 1, succeeds his father Jin Kangdi as emperor of China. His mother, Empress Dowager Chu, becomes the ruling authority at court, and serves as regent.source
• 344Shapur II, for the second time, besieges the Roman fortress of Nisibis in eastern Mesopotamia, but is repulsed by forces under General Lucilianus.source
• 344Gye becomes king of the Korean kingdom of Baekje.source
• 344The Eastern Roman Emperor Constantius II campaigns in eastern Mesopotamia, against the Sassanid Persians.source
• 346Geunchogo becomes king of the Korean kingdom of Baekje.source
• 346In Korea, the Buyeo Kingdom is absorbed by Goguryeo.source
• 347Li Shi, ruler of Cheng Han, fails in his attempt to halt a Jin expedition under Huan Wen. He flees to the capital Chengdu and surrenders his forces. Emperor Jin Mudi spares his life and makes him a marquess.source
• 348In Persia, women are enrolled in the army to perform auxiliary services.source
• 348In India, Samudragupta of the Gupta Empire defeats Rudrasena in battle.source
• 350January – Constans I flees towards Spain, where he is subsequently assassinated at Castrum Helenae. Magnentius rules the Western portion of the Roman Empire and is far more tolerant towards Christians and Pagans alike.source
• 350The city of Anbar (Iraq) is founded by king Shapur II.source
• 350The Ran Wei-Later Zhao war breaks out in North China. Ethnic Han ruler Ran Min had used the infighting between the brothers who reigned in quick succession as emperors of the Jie state of the Later Zhao to assume power, establish the Ran Wei dynasty, have an alleged 200,000 non-Han subjects (mostly Jie and Xiongnu) massacred and end the Later Zhao dynasty. This situation will soon be exploited by the neighbouring state of Former Yan which expands from the northeast towards the Yellow River.source
• 350About this time the Huns begin to invade the Sassanid Empire.source
• 351May 7 – The Jewish revolt against Constantius Gallus breaks out. After his arrival at Antioch, the Jews begin a rebellion in Palestine. The Roman garrison in the town of Diocesarea is wiped out.source
• 351September 28 – Battle of Mursa Major: Constantius II defeats the usurper Magnentius along the valley of the Drava. The battle is one of the bloodiest in Roman military history. During the fighting Marcellinus, a general of Magnentius is killed; Magnentius himself survives.source
• 351Winter – Magnentius flees to Aquileia in northern Italy and fortifies the mountain passes in the Alps.source
• 351Constantius II marches West with a large field army (around 60,000 men) to topple Magnus Magnentius in Pannonia.source
• 352By the end of the year Constantius enters Milan.source
• 352The Alamanni and the Franks cross the Rhine and defeat the depleted Roman units left at the frontier. The Germans take control of around 40 towns and cities between the Moselle and the Rhine.source
• 352Constantius Gallus sends his general (magister equitum) Ursicinus to forcefully put down the Jewish revolt in Palestine. The rebels destroy the cities Diopolis and Tiberias, while Diocesarea is razed to the ground. Ursicinus gives the order to kill thousands of Jews, even children. After the revolt, a permanent garrison is stationed in Galilee.source
• 352Emperor Constantius II invades northern Italy in pursuit of the usurper Magnus Magnentius, who withdraws with his army to Gaul. He declares an amnesty for Magnentius' soldiers, many of whom desert to him.source
• 352War begins between the Huns and the Alans.source
• 353Battle of Mons Seleucus: Emperor Constantius II defeats the usurper Magnentius, who commits suicide in Gaul in order to avoid capture. Constantius becomes sole emperor, and reunifies the Roman Empire.source
• 354As a result of the armies of the West having been largely withdrawn by the usurper Magnus Magnentius, to fight Constantius II, hordes of barbarians (Franks and Alemanni) cross the upper Rhine into Gaul and invade the lands of the Helvetians.source
• 354Fu Sheng, emperor of the Former Qin, reigns in northern China.source
• 355The Lentienses, a Germanic tribe, are fined by the Roman commander Arbetio under Constantius II for several incursions against the Roman Empire.source
• 355The Franks besiege Colonia Agrippinensium for ten months.source
• 356Winter – Siege of Senonae: Julian over-winters at Senonae (Bourgogne). German federated troops (foederati) desert and hostile warbands besiege the town.source
• 356Siege of Autun: Julian receives a report that Augustodunum (Autun) is under attack by the Alemanni. The city walls are in poor state and in danger of falling.source
• 356Naemul becomes king of the Silla dynasty (Three Kingdoms of Korea).source
• 356Battle of Reims: Julian is defeated by the Alemanni at Reims (Gaul).source
• 356Rhaetia (Switzerland) is invaded by the Alemanni.source
• 356Battle of Brumath: Roman forces pursue Germanic warbands through the Gallic countryside. Julian wins an open battle near Brumath (Alsace).source
• 357The Alans rout the Hun army in Western Asia.source
• 357Summer – Battle of Strasbourg: Julian, Caesar (deputy emperor) and supreme commander of the Roman army in Gaul, wins an important victory against the Alemanni at Strasbourg (Argentoratum), driving the barbarians back behind the Rhine.source
• 357At about this date, Basil of Caesarea visits Egypt.source
• 357Winter – Constantius II receives ambassadors from the Persian Empire. They demand that Rome restore the lands surrendered by King Narseh.source
• 357Saran, King of Ulster, is overthrown.source
• 358An invasion of Pannonia by the Quadi and the Sarmates is repulsed by Constantius II.source
• 359Siege of Amida: Shapur II besieges the Roman fortress of Amida (modern Diyarbakir). After seventy-three days the city is conquered and the population is massacred by the Persians. Ammianus Marcellinus is a fortunate survivor and flees to Singara (Iraq).source
• 359Winter – Shapur II halts his campaign, due to heavy casualties during the Persian invasion.source
• 359King Shapur II the Great of the Persian Empire invades southern Armenia. The Romans implement a scorched earth policy and place strong guards at the Euphrates crossings.source
• 360The Huns invade the Pontic steppes by the thousands, spreading terror as they take over territories held for generations by Alans, Heruls, Ostrogoths and Visigoths.source
• 360King Shapur II continues his campaign against the Roman fortresses, capturing Singara, Bezabde and Nisibis.source
• 360The Alamanni raid Raetia (Switzerland), but are pushed back behind the Rhine by Julian, into the Black Forest.source
• 361July – Julian begins leading his troops eastwards against Constantius II.source
• 362July 18 – Emperor Julian arrives at Antioch with an expeditionary force (60,000 men), and stays there for nine months, to launch a campaign against the Persian Empire. He secures the co-operation of King Arsaces of Armenia, who fights a bloody guerrilla war against the Persians.source
• 363March 5 – Emperor Julian departs from Antioch with his army (90,000 men) and heads north towards the Euphrates. En route he creates a diversion and sends a force of 30,000 soldiers under his cousin Procopius to Armenia.source
• 363May 29 – Battle of Ctesiphon: Julian reaches the vicinity of the strongly fortified capital Ctesiphon. King Shapur II in charge of a large Persian army adopts a scorched earth policy, leaving the Romans desperately short of supplies.source
• 363June 16 – The Roman army starts its retreat northward to Corduene (Armenia). Julian marches back up the Tigris and burns his fleet of supply ships. During the withdrawal Julian's forces suffer several attacks from the Persians.source
• 363Egyptian rose in revolt against Roman occupation, armed clashes occur.source
• 363Emperor Jovian negotiates a disastrous peace with Persia, surrendering four of the five Roman provinces gained by Caesar Galerius in 298, and the cities Nisibis and Singara (Mesopotamia).source
• 364March 28 – Valens, brother of Valentinian I, is appointed co-emperor (Augustus) in the palace of Hebdomon (Turkey). He rules the Eastern portion of the Roman Empire, from the Danube to the Persian border, and begins the first anti-pagan persecutions.source
• 364Britain is forced to endure fierce barbarian raids.source
• 365November 1 – The Alamanni cross the Rhine and invade Gaul. Emperor Valentinian I moves to Paris to command the army and defend the Gallic cities.source
• 366January 2 – The Alamanni cross the frozen Rhine in large numbers, and invade the Gallic provinces. They capture Alsace and a large part of the Swiss Plateau.source
• 366April – Battle of Thyatira: Emperor Valens defeats the troops of Procopius, bringing an end to his revolt; Serenianus and Marcellus are killed. Procopius flees the battlefield, but is executed by Valens.source
• 366Winter – Emperor Valentinian I appoints Jovinus, his Master of the Horse (Magister Equitum), general of the army. He defeats the Alamanni in three successive battles, and pushes them out of Gaul.source
• 367Winter – Valentinian I mobilises a massive army for his campaign against the Alamanni and the Franks. He summons the Italian and Illyrian legions for a spring offensive.source
• 367Great Conspiracy: The Roman garrison on Hadrian's Wall revolts and allows Picts from Caledonia to devastate Britain. Simultaneously Attacotti, the Scotti from Hibernia (Ireland), and the Saxons from Germania invade the island's mid-western and south-eastern borders. They sack the cities and murder, rape or enslave Romano-British civilians.source
• 367Battle of Solicinium: Emperor Valentinian I launches a punitive expedition against the Alamanni, due to the crises in Britannia and Gaul. The Alamanni re-cross the Rhine and plunder Moguntiacum (modern Mainz).source
• 368Spring – Emperor Valentinian I and his 8-year-old son, Gratian, cross the Rhine with an army into Alamannic territory. He defeats the Alemanni and burns food stores along the border. A temporary peace is signed with Macrian, king of the Bucinobantes, and Valentinian returns to his capital Augusta Treverorum (modern Trier).source
• 368Great Conspiracy: Picts, Scotti and Saxons reach Roman London and plunder the city. Theodosius, a general (Comes Britanniarum), is sent with a relief force to Britannia. He marches from Richborough, Kent, to deal with the invaders.source
• 369King Shapur II occupies the pro-Roman kingdom of Armenia. He besieges Artogerassa in modern Georgia, where Papas (Pap), son of King Arsaces II (Arshak II), defends the fortress and the royal treasure against Persian forces.source
• 369Fritigern becomes king of the Visigoths; amidst hostilities with his rival Athanaric, he asks Valens and the Thracian field army to intervene. They end the civil war, and Fritigern converts to Christianity.source
• 369Goguryeo invades Baekje (approximate date).source
• 370Germanic Invasions: Various Germanic tribes are forced against the northern borders of the Roman Empire as they flee the invading Huns.source
• 370Former Qin conquers Former Yan in China.source
• 370The Huns migrate westward from the Volga into Europe and subjugate the Alans and the Ostrogoths. With their arrival, a tradition of composite bows is introduced.source
• 371The fortified cities of the Danube, with Sirmium (Pannonia) at the forefront, contribute to stop an invasion of the Quadi.source
• 371Baekje forces sack the city of P'yongyang in Goguryeo.source
• 371Sosurim becomes king of Goguryeo.source
• 371The Persian Empire attains the zenith of its power under King Shapur II as the Romans renew their war against Persia. Hostilities will continue for the next 5 years.source
• 372The Huns attack the Tervingi on the Dniester, overwhelming them with light cavalry (horse archers), and devastating the settlements of the Goths. King Athanaric is defeated and seeks refuge in Caucaland in the Carpathian Mountains.source
• 372Sixteen Kingdoms: Jin Feidi is dethroned as emperor of the Eastern Jin Dynasty. He is replaced by his granduncle Sima Yu, who is installed as Jin Jianwendi.source
• 372Emperor Valentinian I is engaged in operations against the Alamanni, Quadi and Sarmatians, while his subordinates are dealing with the Roman usurper Firmus in Africa and the Picts in Britain.source
• 373Battle of the Tanais River: The Huns defeat the Alans near the Don, sending the remnants fleeing westward.source
• 373King Shapur II declares war as a result of Valens' support of Armenia. Emperor Valens makes Antioch his military base for the campaign against Persia.source
• 375Geungusu becomes king of the Korean kingdom of Baekje.source
• 375In Africa, the dissident Berber prince Firmus is delivered to the Romans by his brother Gildon.source
• 376The Greuthungi, led by Alatheus and Saphrax, displaced by the predations of the Huns and Alans, request asylum within the Roman Empire. They are refused. The Roman frontier forces stretched to the breaking point, they slip across the Danube and unite with Fritigern. With their situation critical and desperately short of food, discontent is rising amongst the Goths.source
• 376Lupicinus, count (Comes) of Thrace, tries to bring the Visigoths back under control. He invites Fritigern and the Gothic leaders to a banquet, letting them believe that in addition to food and drink, they can discuss provisions for their people. During the feast, Lupicinus tries to assassinate the Gothic delegation. Fritigern escapes and the Goths begin looting and burning the farms and Roman villas near Marcianople.source
• 376Zhang Tianxi, ruler of Former Liang, submits to Fu Jiān of Former Qin, thus ending the state of Former Liang. Zhang is made "Marquess of Guiyi".source
• 376The Romans fail to disarm the Visigoths, bungle administration of the refugees, and mistreat them, taking some of their children as slaves. The Goths break out of their containment area along the Danube and strike south towards the low-lying fertile region near Marcianople (Bulgaria). Although defying the local Roman officials, they are not in open revolt.source
• 376Fearing they will join Fritigern, Roman troops of Gothic origin stationed in Adrianople are ordered by Valens to move east. The soldiers request a two-day delay to prepare and ask for food and money for the journey. However, the chief magistrate of Adrianople refuses and the Goths break out in open rebellion. They inflict heavy casualties among the citizens. Arming themselves with Roman equipment, they join forces with Fritigern.source
• 376Gothic War: Emperor Valens permits the Visigothic chieftain Fritigern and his people to cross the Danube from Thrace (later Romania), and settle on Roman soil in Lower Moesia, on the condition that they provide soldiers to the legions. The Visigoths embark by troops on boats and rafts, and canoes made from hollowed tree trunks. The river is swollen by frequent rains; a large number try to swim and are drowned in their struggle against the force of the stream.source
• 376Winter – Fritigern attempts an unsuccessful siege of Adrianople. His troops try to storm the city walls, but abandon the attacks and break into small bands, better able to forage and feed themselves. Roman prisoners switch sides and give the Goths a valuable source of local intelligence.source
• 376Lupicinus attacks the Visigoths 9 miles outside Marcianople with hastily gathered local troops. His force (5,000 men) is annihilated and the Goths equip themselves with Roman armour and weapons. Fritigern marches south towards Adrianople (Turkey).source
• 377Valens sends Saturninus to the Balkan Mountains to block the passes. These efforts are possibly supported by units of limitanei (light infantry) withdrawn from areas under Goth control. Split into small bands and unable to join the Tervingi in sufficient strength to overcome the Roman cordon, the Goths grow increasingly desperate.source
• 377Valens concludes a peace with the Persian Empire and leaves enough troops to defend the eastern frontier. The Saracens under Queen Mavia revolt and devastate a swath of territory stretching from Phoenicia and Palestine as far as the Sinai (Egypt). Valens successfully brings the uprising under control.source
• 377Battle of the Willows: The Romans abandon the guerrilla strategy and are attacked by the Goths. The battle is indecisive but both sides suffer heavy casualties. The only Roman army available to face the Goths is no longer a fighting force. Richomeres withdraws his troops south of Marcianople (Bulgaria).source
• 377Emperor Valens requests his nephew Gratian to send Roman troops against the Goths. He responds by sending the ageing General Frigeridus with elite reinforcements that Ammianus calls ‘Pannonian and Transalpine auxiliaries (Pannonicis et Transalpinis auxiliis).’ Gratian also sends Richomeres, his Frankish commander of household troops (comes domesticorum), at the head of a number of troops drawn from the Gallic field army.source
• 377Persian king Shapur II pushes the Huns back across the Caucasus.source
• 377Autumn – Bands of predatory "barbarians" spread throughout the province in search of food, supplies and booty. Most Roman troops are bottled up in the towns. Some elite units remain in the field and skirmish with the Goths. One such action takes place outside the town of Dibaltum. The Scutarii heavy cavalry is destroyed in a mad charge against the Goths.source
• 378February – The Lentienses (part of the Alemanni) cross the frozen Rhine and raid the countryside. They are driven back by Roman auxilia palatina (Celtae and Petulantes), who defend the western frontier.source
• 378May – Battle of Argentovaria: Emperor Gratian is forced to recall the army he has sent East. The Lentienses are defeated by Mallobaudes near Colmar (France). Gratian gains the title Alemannicus Maximus.source
• 378July – Frigeridus, Roman general, fortifies the Succi (Ihtiman) Pass to prevent the "barbarians" from breaking out to the north-west (Pannonia).source
• 378August 9 – Battle of Adrianople: Valens leads an elite Roman army to Thrace to confront revolts, but is defeated.source
• 378August – Gratian continues down the Danube to the "Camp of Mars" (frontier fortress near modern Niš), where he loses several men in an ambush by a band of Alans.source
• 378Siyaj K'ak' conquers Tikal on January 16.source
• 378Siyaj K'ak' conquers Waka on January 8.source
• 378Spring – Emperor Valens returns to Constantinople and mobilises an army (40,000 men). He appoints Sebastianus, newly arrived from Italy, as magister militum to reorganize the Roman armies in Thrace.source
• 378The Goths, with their wagons and families vulnerable to attack, withdraw back to the north. Roman scouts fail to detect the Greuthungi cavalry foraging further up the Tundzha valley.source
• 378Gothic War: Valens sends Sebastian with a body of picked troops (2,000 men) to Thrace and renews the guerrilla war against the Goths. He chases down small groups of Gothic raiders around Adrianople.source
• 378Siyaj K'ak' conquers Uaxactun.source
• 378The Goths, supported by the Huns, move on to Constantinople. Their progress is checked by the Saracens, recruited from Arab tribes who control the eastern fringes of the empire.source
• 378Siyaj K'ak' begins to replace Mayan kings with relatives of Spearthrower Owl, emperor of Teotihuacan.source
• 378Fritigern strikes south from Cabyle, following the Tundzha River towards Adrianople, and tries to get behind the supply lines to Constantinople.source
• 379September 13 – Yax Nuun Ayiin (I) becomes ruler of Tikal.source
• 379Former Qin captures the city of Xiangyang from Eastern Jin. The Buddhist monk Dao'an is transferred from Xiangyang to Chang'an.source
• 379Britain is forced to endure fierce Barbarian raids.source
• 380November 24 – Theodosius I makes his adventus, or formal entry, into Constantinople.source
• 380Battle of Thessalonica: The Goths under Fritigern defeat a Roman army in Macedonia. Theodosius I retreats to Thessalonica and leaves Gratian in control of the Western Roman Empire.source
• 380Queen Mavia, with her Saracen forces, defeats the Roman army in southern Syria.source
• 380Rome's enemies (the Germans, Sarmatians and Huns) are taken into Imperial service; as a consequence, barbarian leaders begin to play an increasingly active role in the Roman Empire.source
• 381The Sciri together with the Huns attack along Rome's lower Danubian frontier.source
• 383August 25 – Emperor Gratian, age 24, is assassinated at Lugdunum (modern-day Lyon), leaving a young widow Laeta. Pannonia and Africa maintain their allegiance to co-emperor Valentinian II, now 12, whose mother, Justina, rules in his name.source
• 383Magnus Maximus withdraws Roman troops from the region of Wales, marking the effective end of Roman rule in Wales.source
• 383Emperor Theodosius I cedes Dacia and Macedonia to Valentinian II. They recognize Magnus Maximus as Augustus.source
• 383Battle of Fei River (Feishui): Former Qin forces are defeated by the numerically inferior Eastern Jin army in Anhui, preserving the Jin state in the south and precipitating the destruction of Former Qin in the north.source
• 384Magnus Maximus returns to Britain to aid the Roman army with the barbarian raids triggered by Maximus' withdrawal of troops to the continent.source
• 384Quintus Aurelius Symmachus becomes urban prefect of Rome.source
• 384Following Former Qin's defeat at the Battle of Fei River, Murong Chui, Murong Hong, and Yao Chang declares themselves emperors of Later Yan, Western Yan, and Later Qin respectively, precipitating the disintegration of Former Qin.source
• 385Jinsa of Baekje becomes the 16th king of the ancient Korean kingdom of Baekje.source
• 386Magnus Maximus invades Italy; he destroys Novara for supporting his rival Valentinian II.source
• 386The fight in the Roman Empire against anti-pagan laws becomes increasingly futile.source
• 387Spring – Emperor Theodosius I increases the taxes in Antioch. A peasant uprising leads to a riot, and public buildings are set afire. Theodosius sends imperial troops to quell the disturbance, and closes the public baths and theatres.source
• 387Magnus Maximus, usurping emperor of the West, invades Italy. Emperor Valentinian II, age 16, is forced out of Rome. He flees with his mother Justina and sisters to Thessaloniki (Thrace).source
• 388August 28 – Magnus Maximus surrenders at Aquileia, and is executed. Theodosius I devotes himself to gluttony and voluptuous living. Maximus' son Flavius Victor is executed at Trier, by Valentinian's magister militum Arbogast.source
• 388A group of Christians storms the synagogue of the city Callinicum (Syria), at the Euphrates.source
• 388Emperor Chandragupta II, ruler of the Gupta Empire, begins a war against the Shaka Dynasty in West India.source
• 388Frankish invasion of 388: Rebellious Franks led by Marcomer, Sunno and Genobaud invade the Roman Empire with plunder and threaten Colonia Claudia Ara Agrippinensium (Cologne). A part of the invaders are destroyed by the Romans in the charcoal forest (present-day Belgium). The Roman general Quintines pursues the invaders on Frankish soil and is ambushed. His army is surrounded and defeated by the Franks.source
• 388Battle of the Save: Emperor Theodosius I defeats Magnus Maximus near Emona (modern Slovenia). Theodosius is in command of an army including Goths, Huns and Alans. Valentinian II, now 17, is restored as Roman Emperor.source
• 390April – Massacre of Thessalonica: Resentment among the citizens of Thessalonica (Macedonia) breaks out into violence after the arrest of a popular charioteer. Butheric, military commander of Illyricum, is murdered. Emperor Theodosius I orders vengeance, despite the pleas for mercy by Ambrose, bishop of Milan; more than 7,000 inhabitants are massacred by the Roman army.source
• 390The Visigoths and Huns, led by Alaric, invade Thrace. Stilicho, high-ranking general (magister militum) of Vandal origin, raises an army and begins a campaign against the Goths.source
• 391A Rouran chief named Heduohan (曷多汗) is defeated and killed in battle against the Tuoba Northern Wei Dynasty. Surviving Rouran move west towards the Gaoche, led by Heduohan's brother and successor, Shelun.source
• 392Asin becomes king of the Korean kingdom of Baekje.source
• 392Stilicho, Roman general (magister militum), defeats the Visigoths and Huns in Thrace. Emperor Theodosius I permits Alaric to go free on condition he provides, as foederati, military services to the Roman Empire.source
• 393Yao Xing succeeds Yao Chang as emperor of the Later Qin Empire.source
• 394September 6 – Battle of the Frigidus: Emperor Theodosius I defeats and kills the usurper Eugenius. The forces of Theodosius are bolstered by numerous auxiliaries, including 20,000 Visigoth federates under Alaric. The Frankish general Arbogast (magister militum) escapes into the Alps and commits suicide.source
• 394Late Roman army: The Notitia Dignitatum shows the development of forces in the Roman Empire. By now 200,000 soldiers guard the borders, and a reserve force of 50,000 is available for deployment. Many non-Roman soldiers are from Germanic tribes: Alamanni, Franks, Goths, Saxons and Vandals.source
• 394The last ruler of Former Qin, Fu Chong, is killed in battle against an army of Western Qin, bringing Former Qin to an end.source
• 394Winter – 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.source
• 395December 8 – Later Yan is defeated by its former vassal Northern Wei at the Battle of Canhe Slope, during the Southern and Northern Dynasties period of China.source
• 395The Huns begin their large-scale attack on the Eastern Roman Empire. They invade Armenia, Cappadocia, and enter parts of Syria, threatening Antioch.source
• 395Alaric besieges Constantinople. After commitments from Rufinus, the Pretorian prefect of the East, and chief adviser to Arcadius, the Goths move further west.source
• 395Stilicho 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 forbade Stilicho to attack Alaric and demandes that his army leave the territory of the East Roman Empire.source
• 395King Rudrasimha III, ruler of the Western Satraps (India), is defeated by the Gupta Empire.source
• 395The Goths, led by Alaric, invade and devastate Thrace and Macedonia and impose a tribute on Athens.source
• 395Alaric, 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.source
• 396Stilicho, Roman general (magister militum), controls the young emperor Honorius as his regent, and becomes the de facto ruler of the Western Roman Empire. He enlists the Alemanni and the Franks, to defend the Rhine frontier.source
• 396Revolt of Alaric I: The Visigoths, led by Alaric I, rampage through Greece and plunder Corinth, Argos and Sparta. They destroy the Temple of Eleusis, and harry the Peloponnese. Stilicho makes peace with the Goths, and allows them to settle in Epirus (Balkans).source
• 397Revolt 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.source
• 398Gildonic 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. 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.source
• 398Eutropius, Roman general (magister militum), celebrates his victory over the Huns ("the wolves of the North") in a parade through Constantinople (see 395).source
• 398Possible date for the Second Pictish War.source
• 399Xianbei kingdom of Southern Yan conquers Qing Province (modern central and eastern Shandong) from the Eastern Jin.source