|Centuries:||4th century – 5th century – 6th century|
|Decades:||400s 410s 420s – 430s – 440s 450s 460s|
|Years:||428 429 430 – 431 – 432 433 434|
|431 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1184|
|Bahá'í calendar||−1413 – −1412|
|English Regnal year||N/A|
|Chinese calendar||庚午年 (Metal Horse)
3127 or 3067
— to —
辛未年 (Metal Goat)
3128 or 3068
|- Vikram Samvat||487–488|
|- Shaka Samvat||353–354|
|- Kali Yuga||3532–3533|
|Igbo calendar||−569 – −568|
|Iranian calendar||191 BP – 190 BP|
|Islamic calendar||197 BH – 196 BH|
|Minguo calendar||1481 before ROC
|Thai solar calendar||974|
|Wikimedia Commons has media related to 431.|
Year 431 (CDXXXI) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Bassus and Antiochus (or, less frequently, year 1184 Ab urbe condita). The denomination 431 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.
- Flavius Aetius, Roman general (magister militum), fights a campaign in Rhaetia (Switzerland) and Noricum (Austria). He is attested in the city of Vindelicia (modern Augsburg), reestablishing Roman rule on the Danube frontier.
- Aetius pushes the Salian Franks back across the River Somme. King Chlodio signs a peace treaty and becomes a foederati of the Western Roman Empire.
- Hippo Regius becomes the capital of the Vandal Kingdom. After 14 months, hunger and disease the Vandals ravaged the city. Emperor Theodosius II sends an imperial fleet with an army under command of Aspar and lands at Carthage.
- Aspar is routed by the Vandals and Flavius Marcian, future Byzantine emperor, is captured during the fighting. He negotiates a peace with king Genseric and maintains imperial authority in Carthage.
Arts and Sciences
- June – First Council of Ephesus: Nestorianism is rejected, the Nicene creed is declared to be complete. Nestorius is deposed from his see.
- October 1 – Maximianus is enthroned as Patriarch of Constantinople.
- Pope Celestine I dispatches Palladius to serve as bishop to the Irish.
- June 22 – Paulinus of Nola, Christian bishop and poet (b. 354)
- Qifu Mumo, prince of the Chinese Xianbei state Western Qin