|280 by topic|
|Ab urbe condita||1033|
|Balinese saka calendar||201–202|
|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||201–202|
|- Kali Yuga||3380–3381|
|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|
406 or 25 or −747
— to —
407 or 26 or −746
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.
- Roman usurper Proculus 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 Wu of the Jin dynasty completes the unification of China, which was previously divided between three contending powers during the Three Kingdoms period. The Jin dynasty's capital of Luoyang becomes a thriving centre of commerce as foreign diplomats and traders travel there.
- Saint George, Roman soldier and Christian martyr (approximate date)
- Yao Yizhong, Chinese general and warlord (d. 352)
- Bonosus, Roman general and usurper
- Cen Hun, Chinese official and politician
- Julius Saturninus, Roman usurper
- Kang Senghui, Chinese monk and translator
- Lu Jing, Chinese general and writer (b. 250)
- Maharaja Sri-Gupta of the Gupta Empire
- Yu Zhong (or Shifang), Chinese general
- Zhang Ti (or Juxian), Chinese chancellor