|Centuries:||3rd century – 4th century – 5th century|
|Decades:||320s 330s 340s – 350s – 360s 370s 380s|
|Years:||347 348 349 – 350 – 351 352 353|
- January 18 – Emperor Constans I is very unliked. Magnus Magnentius is made emperor at Autun (Gaul).
- January – Constans I runs away to Spain. He is killed. Magnentius rules the Western Roman Empire. He is nicer to Christians and Pagans.
- March 1 – Vetranio is asked by Constantina to make himself Caesar. Constantius accepts the new emperor.
- June 3 – Iulius Nepotianus, Roman usurper, calls himself "emperor". He enters Rome with a group of gladiators.
- June 30 – Nepotianus is defeated and killed by Marcellinus.
- December 25 – Vetranio meets Constantius II at Naissus (Serbia). He is forced to give up his title.
- About this time the Huns begin to invade the Sassanid Empire.
- The city of Anbar (Iraq) is founded by king Shapur II.
- The Wei-Jie war breaks out in North China.
- The church of Santa Constanza in Rome is finished.
- Honoratus, archbishop of Arles (approximate date)
- Hypatia of Alexandria, female Neoplatonist philosopher (approximate date)
- Murong Wei, emperor of the Xianbei state Former Yan (d. 385)
- Plutarch of Athens, Greek philosopher (approximate date)
- Theodore of Mopsuestia, bishop and theologian (approximate date)
- Zhang Xuanjing, ruler of the Chinese state Former Liang (d. 363)
- Roberts, J: "History of the World.". Penguin, 1994.