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The 310s

143 sourced entries across 10 years, inside the 4th century. Each year below opens its own page; the lines under it are that year’s highest-ranked entries.

310 CE18 entries

  • April 18 – Pope Eusebius succeeds Pope Marcellus I as the 31st pope, but is banished on August 17 by the Emperor Maxentius to Sicily, where he dies, perhaps from a hunger strike.
  • July – 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.
  • At Trier, Constantine orders the minting of a new coin, the solidus, in an effort to offset the declining value of the denarius and bring stability to the imperial currency by restoring a gold standard. The solidus (later known as the bezant) will be minted in the Byzantine Empire without change in weight or purity until the 10th century.

311 CE16 entries

  • April 30 – On his deathbed, Emperor Galerius declares religious freedom and issues the Edict of Serdica, ending the Diocletianic Persecution of Christians in the eastern half of the Roman Empire.
  • May 5 – Galerius dies at age 51 from a gruesome disease, possibly colorectal cancer or Fournier gangrene.
  • July 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.

312 CE15 entries

  • October 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.
  • October 29 – Constantine enters Rome; he stages a grand adventus in the city, and is met with popular jubilation. Maxentius' body is fished out of the Tiber and decapitated.
  • Constantine I promotes a policy of state sponsorship of Christianity, perhaps even becoming a Christian himself (see Constantine the Great and Christianity).

313 CE20 entries

314 CE13 entries

  • January 10 – Pope Miltiades' reign ends.
  • January 31 – Pope Sylvester I succeeds Pope Miltiades as the 33rd pope.
  • August 30 – Council of Arles: Confirms the pronouncement of Donatism as a schism, and passes other canons.

315 CE17 entries

  • July 25 – The Arch of Constantine is completed near the Colosseum at Rome to commemorate Constantine's victory over Maxentius at the Milvian Bridge. As part of the ceremony Constantine is expected to make a sacrifice to Rome's traditional gods, but he refuses to do so.
  • Crucifixion is abolished as punishment in the Roman Empire.
  • Constantine the Great and co-emperor Licinius battle the Sarmates, the Goths and the Carpians along the Danube. Constantine leads a punitive expedition into Dacia and reestablishes the Roman fortifications of the frontier.

316 CE15 entries

  • October 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.
  • December – Battle of Mardia: Constantine I defeats his rival Licinius and senior officer Valerius Valens, near the town of Harmanli (Bulgaria).
  • Han-Zhao forces capture Chang'an, capital of the Chinese Western Jin dynasty. Emperor Min of Jin surrenders to Liu Yao, ending the Western Jin.

317 CE9 entries

  • March 1 – Emperor Constantine the Great and co-emperor Licinius elevate their sons Crispus, Constantine II and Licinius II to Caesars. After this arrangement Constantine rules the dioceses Pannonia and Macedonia, and establishes his residence at Sirmium, from where he prepares a campaign against the Goths and Sarmatians.
  • Sixteen 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.
  • The earliest historically verified reference to tea is recorded, although the Chinese have been drinking the beverage for centuries.

318 CE13 entries

  • Gregory the Illuminator appoints his son Aristax as successor in the patriarchate of Armenia.
  • Liu Yao becomes the new emperor of Han-Zhao and moves his capital to Chang'an.
  • Emperor Constantine the Great gives the ancient Roman town Drepana (Asia Minor) the name Helenopolis, after his mother Helena, and builds a church in honour of the martyr St. Lucian.

319 CE7 entries

  • Arius travels to Nicomedia at the invitation of Bishop Eusebius, after having been accused of heresy and condemned by Alexander, the Patriarch of Alexandria. This gives rise to the Arian Controversy.
  • Christianity is introduced in Colchis, present-day Georgia.
  • Emperor Constantine the Great prohibits the separation of the families of slaves, during a change in ownership.