Year 415 (CDXV) was a common year starting on Friday (link will display the full calendar) 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.
|Ab urbe condita||1168|
|Balinese saka calendar||336–337|
|Chinese calendar||甲寅年 (Wood Tiger)|
3111 or 3051
— to —
乙卯年 (Wood Rabbit)
3112 or 3052
|- Vikram Samvat||471–472|
|- Shaka Samvat||336–337|
|- Kali Yuga||3515–3516|
|Iranian calendar||207 BP – 206 BP|
|Islamic calendar||213 BH – 212 BH|
|Minguo calendar||1497 before ROC|
|Seleucid era||726/727 AG|
|Thai solar calendar||957–958|
541 or 160 or −612
— to —
542 or 161 or −611
- 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.
- The Visigoths invade the Iberian Peninsula and begin to conquer territory taken previously by the Vandals. King Ataulf 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. Ataulf is assassinated in the palace while taking a bath. Sigeric succeeds him, but after a reign of seven days he is also murdered.
- Autumn – Wallia, brother of Ataulf, 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.
- 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).
- John Cassian, Christian theologian, settles at a monastery in Marseille (Gaul); he organizes monastic communities after an eastern model.
- The Eustathian schism in Antioch is healed (approximate date).