Year 347 (CCCXLVII) 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 Rufinus and Eusebius (or, less frequently, year 1100 Ab urbe condita). The denomination 347 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||1100|
|Balinese saka calendar||268–269|
|Chinese calendar||丙午年 (Fire Horse)|
3043 or 2983
— to —
丁未年 (Fire Goat)
3044 or 2984
|- Vikram Samvat||403–404|
|- Shaka Samvat||268–269|
|- Kali Yuga||3447–3448|
|Iranian calendar||275 BP – 274 BP|
|Islamic calendar||283 BH – 282 BH|
|Minguo calendar||1565 before ROC|
|Seleucid era||658/659 AG|
|Thai solar calendar||889–890|
473 or 92 or −680
— to —
474 or 93 or −679
- Li Shi, ruler of Cheng Han, fails in his attempt to halt a Jin expedition under Huan Wen. He flees to the capital Chengdu and surrenders his forces. Emperor Jin Mudi spares his life and makes him a marquess.
- Council of Sardica: An attempt is made to resolve the Arian controversy, and ground rules for bishops are laid down.
- The Council of Philippopolis is held as the result of Eastern bishops leaving the Council of Sardica. In Philippopolis (Bulgaria), they excommunicate Pope Julius, and as a result, the Arian controversy is perpetuated.
- January 11 – Theodosius I, Roman Emperor (d. 395)
- March 27 – Saint Jerome, priest and translator of the Bible (approximate date)
- Eunapius, Greek sophist and historian
- John Chrysostom, archbishop of Constantinople (approximate date)
- Paula, Desert Mother and Saint (d. 404)
- Saint Porphyry, bishop of Gaza (approximate date)
- al, Philip Schaff et. Nicene and Post-Nicene Fathers: Series II/Volume II/Socrates/Book II.