|Centuries:||2nd century – 3rd century – 4th century|
|Decades:||220s 230s 240s – 250s – 260s 270s 280s|
|Years:||253 254 255 – 256 – 257 258 259|
|256 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1009|
|Chinese calendar||乙亥年 (Wood Pig)
2952 or 2892
— to —
丙子年 (Fire Rat)
2953 or 2893
|Coptic calendar||−28 – −27|
|- Vikram Samvat||312–313|
|- Shaka Samvat||178–179|
|- Kali Yuga||3357–3358|
|Iranian calendar||366 BP – 365 BP|
|Islamic calendar||377 BH – 376 BH|
|Minguo calendar||1656 before ROC
|Seleucid era||567/568 AG|
|Thai solar calendar||798–799|
|Wikimedia Commons has media related to 256.|
Year 256 (CCLVI) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Claudius and Glabrio (or, less frequently, year 1009 Ab urbe condita). The denomination 256 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.
- Goths invade Asia Minor. Dacia is lost for the Roman Empire.
- Emperor Valerian persecutes Christians.
- The Franks cross the Rhine, the Alamanni reach Milan.
- Cities in the Roman Empire begin to build walls as the defense of the frontiers begins to crumble.
- The Goths appear at the walls of Thessalonica.
- In Africa, the Berbers massacre Roman colonists.
- The future emperor Aurelian inspects and organizes the defenses along the Rhine.
- King Shapur I invades Mesopotamia and Syria. He conquers and plunders Antioch.
- Dura-Europos is destroyed by the Persians.
- The Anatolian city of Zeugma on the Euphrates was sacked by Persian King Shapur I. This was soon followed by a devastating fire and an earthquake and Zeugma was abandoned.
- Peace and unity are finally restored in China with the victories of the Wei Kingdom in the north. The ruling dynasty is worn out by war, and the kingdom is ruled by ministers on their behalf.
- The great pandemic of the Roman world strikes violently in Pontus on the Black Sea and causes enormous loss of life in Alexandria, encouraging thousands to embrace Christianity.
- Pope Stephen I threatens to excommunicate Cyprian, bishop of Carthage, and other bishops in Africa and Asia Minor unless they stop rebaptizing heretics. Cyprian attacks the Pope in a treatise that gains support from the Council of Carthage. He sends envoys to Rome, raising the specter of a schism between the Roman and Carthaginian Churches.
- A Synod of Carthage is held.
- Sun Jun, general of Wu (b. 219)
- Lu Dai, general of Wu
- Lu Ju, general of Wu
- Teng Yin, minister of Wu
- Wang Su, son of Wang Lang
- Guan Lu, famed practicer of divination