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Year 401 (CDI) was a common year starting on Tuesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Vincentius and Fravitus (or, less frequently, year 1154 Ab urbe condita). The denomination 401 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||1154|
|Balinese saka calendar||322–323|
|Chinese calendar||庚子年 (Metal Rat)|
3097 or 3037
— to —
辛丑年 (Metal Ox)
3098 or 3038
|- Vikram Samvat||457–458|
|- Shaka Samvat||322–323|
|- Kali Yuga||3501–3502|
|Iranian calendar||221 BP – 220 BP|
|Islamic calendar||228 BH – 227 BH|
|Minguo calendar||1511 before ROC|
|Seleucid era||712/713 AG|
|Thai solar calendar||943–944|
527 or 146 or −626
— to —
528 or 147 or −625
- Emperor Arcadius sends many gifts to the Hunnish chieftain Uldin, in appreciation of his victory over the Goths and Gainas. Arcadius then allies himself with the Huns.
- Piracy is committed by slave-traders from Galatia (Turkey), along the coasts of Africa.
- The old Legio II Adiutrix, part of which had always been stationed at Aquincum (modern Budapest), is divided into two comitatenses, and shipped to Britannia.
- Stilicho, Roman general (magister militum), leads his army in an extensive campaign against the Vandals in Rhaetia (Switzerland).
- The Temple of Artemis near Selçuk in Ephesus is dismantled.
- November 18 – The Visigoths, led by king Alaric I, cross the Alps and invade northern Italy.
- Emperor Honorius begins to use the city of Ravenna as a temporary center for certain administrative and military functions. The city is chosen because of its proximity to the bulk of the Western Roman army and due to the fact that its relative poverty makes it a less tempting target for barbarian invaders than cities such as Rome or Milan. This event is often misinterpreted as the establishment of Ravenna as a capital. In reality, the capital of the Western Roman Empire was not truly established at Ravenna until 408.
- Kumarajiva, Kuchean Buddhist monk, arrives in Chang'an and begins translating Buddhist texts into Chinese.
- Gillett, Andrew (2001). "Rome, Ravenna and the Last Western Emperors". Papers of the British School at Rome. 69: 131–167. doi:10.1017/S0068246200001781. ISSN 0068-2462. JSTOR 40311008.
- Yanko-Hombach, Valentina; Gilbert, Allan S.; Panin, Nicolae; Dolukhanov, Pavel M. (2006). The Black Sea Flood Question: Changes in Coastline, Climate and Human Settlement. Springer Science & Business Media. p. 635. ISBN 9781402053023.
- "Saint Anastasius I | pope". Encyclopedia Britannica. Retrieved December 25, 2020.