|Centuries:||2nd century – 3rd century – 4th century|
|Decades:||240s 250s 260s – 270s – 280s 290s 300s|
|Years:||271 272 273 – 274 – 275 276 277|
|274 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1027|
|Chinese calendar||癸巳年 (Water Snake)
2970 or 2910
— to —
甲午年 (Wood Horse)
2971 or 2911
|Coptic calendar||−10 – −9|
|- Vikram Samvat||330–331|
|- Shaka Samvat||196–197|
|- Kali Yuga||3375–3376|
|Iranian calendar||348 BP – 347 BP|
|Islamic calendar||359 BH – 358 BH|
|Minguo calendar||1638 before ROC
|Seleucid era||585/586 AG|
|Thai solar calendar||816–817|
Year 274 (CCLXXIV) 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 Aurelianus and Capitolinus (or, less frequently, year 1027 Ab urbe condita). The denomination 274 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.
- Battle of Châlons: Emperor Aurelian reconquers the Gallic Empire (Gaul and Britain). Tetricus I surrenders his army near Châlons-sur-Marne, France. With the conquests of the Palmyrene Empire and the Gallic Empire, the Roman Empire is united again.
- Rome greets Aurelian as Restitutor Orbis ("Restorer of the World") and accords him a magnificent triumph (victory procession), which is graced by his captives Tetricus I and his son Tetricus II.
- Aurelian issues an important reform of Roman currency.
- Germanic tribes take advantage of the destroyed Roman forces of the Rhine. They pillage and depopulate large areas of Gaul, including Paris. The Rhine border is lost for 20 years. Franks live in the area of present southern Netherlands, northern Belgium and Rhineland from now on.
- December 25 – Aurelian has a temple dedicated to Sol Invictus on the third day after the solstice and day of rebirth of the Sun. This religion, which is in essence monotheistic, becomes the state religion of Rome.
- Britain rebels over the value of coinage.
- March 2 – Mani, a sage of Persia dies at Gundeshapur after 30 years of preaching his "heresy" at the court of the late Sassanian King Shapur I and on long journeys to Khorasan, India and China. He is executed or allowed to die in prison, and claims to be a prophet of God. Mani combines Zoroastrian dualism with Christian theology and his disciples gain wide support Manichaeism despite opposition from Byzantine and Roman Emperors.
- December 30 – Pope Felix I dies in Rome after a 5-year reign.
- Japanese shipwrights build a 100-foot oar-powered vessel for Emperor Ōjin. The Japanese will not use sails for another seven centuries.
- Li Xiong, first emperor of Cheng Han (d. 334)
- Shi Le, founder and emperor of the Chinese Jie state (d. 333)
- March 2 – Mani, prophet and founder of Manichaeism (b. 216)
- August 25 – Empress Yang Yan, first wife of Emperor Wu of Jin (b. 238)
- December 30 – Pope Felix I
- Cao Fang, third ruler of the state of Cao Wei (b. 232)
- Lu Kang, general of the state of Eastern Wu (b. 226)