415

Year 415 (CDXV) was a common year starting on Friday of the Julian calendar. At the time, it was known as the Year of the Consulship of Honorius and Theodosius (or, less frequently, year 1168 Ab urbe condita). The denomination 415 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

• Constantius, Roman general (magister militum), drives the Visigoths out of Gaul. He captures the usurper Priscus Attalus, and sends him under military escort to Ravenna.^{[citation needed]}
• The Visigoths invade the Iberian Peninsula and begin to conquer territory taken previously by the Vandals. King Athaulf and his pregnant wife Galla Placidia leave Gallia Narbonensis; they relocate at Barcelona. Their infant son, Theodosius, dies in infancy, eliminating an opportunity for a Roman-Visigothic line. Athaulf is assassinated in the palace while taking a bath. Sigeric succeeds him, but after a reign of seven days he is also murdered.^{[citation needed]}
• Autumn – Wallia, brother of Athaulf, becomes king of the Visigoths. He accepts a peace treaty with emperor Honorius, in return for a supply of 600,000 measures of grain. After the negotiations he sends Placidia to Rome with hostages.^{[citation needed]}

• March 18 – The Daysan River floods Edessa, Mesopotamia.^{[citation needed]}

• March – Hypatia of Alexandria, Neoplatonist philosopher, is murdered by a Christian mob of Nitrian monks at the church (former temple conceived by Cleopatra VII) called Caesareum. Having driven out the Jews, Alexandria's new patriarch, Cyril, has instigated the mob after taking offense at Hypatia's scientific rationalism (approximate date).^{[citation needed]}
• John Cassian, Christian theologian, settles at a monastery in Marseille (Gaul); he organizes monastic communities after an eastern model.^[1]
• The Eustathian schism in Antioch is healed (approximate date).^{[citation needed]}

• March – Hypatia of Alexandria, female Neoplatonist philosopher, murdered
• August 15 – Athaulf, king of the Visigoths, assassinated
• August 22 – Sigeric, king of the Visigoths, assassinated
• Chandragupta II, emperor of the Gupta Empire (India)
• Thermantia, Roman empress
• Tufa Rutan, Chinese prince of the Southern Liang (b. 365)