|Centuries:||2nd century – 3rd century – 4th century|
|Decades:||250s 260s 270s – 280s – 290s 300s 310s|
|Years:||277 278 279 – 280 – 281 282 283|
|280 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1033|
|Chinese calendar||己亥年 (Earth Pig)
2976 or 2916
— to —
庚子年 (Metal Rat)
2977 or 2917
|Coptic calendar||−4 – −3|
|- Vikram Samvat||336–337|
|- Shaka Samvat||202–203|
|- Kali Yuga||3381–3382|
|Iranian calendar||342 BP – 341 BP|
|Islamic calendar||353 BH – 352 BH|
|Minguo calendar||1632 before ROC
|Seleucid era||591/592 AG|
|Thai solar calendar||822–823|
Year 280 (CCLXXX) was a leap 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 Messalla and Gratus (or, less frequently, year 1033 Ab urbe condita). The denomination 280 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.
- Proculus, Roman usurper, starts a rebellion at Lugdunum (Lyon, France) and proclaims himself emperor.
- Emperor Probus drives the Alans off to Asia Minor and suppresses the revolt in Gaul; Proculus is executed.
- The Germans destroy the Roman fleet on the Rhine; Bonosus is proclaimed emperor at Colonia Agrippina (Cologne).
- Probus defeats the army under Bonosus. Bonosus sees no way out and hangs himself. His family is treated with honours.
- Julius Saturninus, governor of Syria, is in Alexandria, charged with the defense of the East. He is declared emperor and withdraws to Apamea. Probus besieges the city and puts him to death.
- Roman territory is under constant threat of raids from Franks. The cities in Gaul are reinforced with defensive walls.
- Emperor Sima Yan occupies most of the southern Kingdom of Wu and unites the Chinese Empire under one rule; he founds the Western Jin Dynasty. Ending the period of the Three Kingdoms, the capital becomes the old and prosperous city of Luoyang. It is a thriving centre of commerce, and ambassadors from throughout the world arrive there.
- King Bahram II of the Sassanid Empire (Persia) sends envoys to seek peaceful relations with Rome.
- The Gupta Empire (India) is founded (approximate date).
Arts and sciences
- Bonosus, Roman usurper
- Cen Hun, minister of the Kingdom of Wu
- Julius Saturninus, Roman usurper
- Kang Senghui, Buddhist monk and translator
- Maharaja Sri-Gupta of the Gupta dynasty
- Proculus, Roman usurper
- Zhang Ti, Chancellor of the Kingdom of Wu (b. 236)