| Millennium: | 1st millennium |
|---|---|
| Centuries: | 2nd century – 3rd century – 4th century |
| Decades: | 240s 250s 260s – 270s – 280s 290s 300s |
| Years: | 275 276 277 – 278 – 279 280 281 |
| 278 by topic | |
| Politics | |
| State leaders – Sovereign states | |
| Birth and death categories | |
| Births – Deaths | |
| Establishment and disestablishment categories | |
| Establishments – Disestablishments | |
| Gregorian calendar | 278 CCLXXVIII |
| Ab urbe condita | 1031 |
| Armenian calendar | N/A |
| Assyrian calendar | 5028 |
| Bahá'í calendar | -1566–-1565 |
| Bengali calendar | -315 |
| Berber calendar | 1228 |
| English Regnal year | N/A |
| Buddhist calendar | 822 |
| Burmese calendar | -360 |
| Byzantine calendar | 5786–5787 |
| Chinese calendar | 丁酉年十一月廿一日 (2914/2974-11-21) — to —
戊戌年十二月初一日(2915/2975-12-1) |
| Coptic calendar | -6–-5 |
| Ethiopian calendar | 270–271 |
| Hebrew calendar | 4038–4039 |
| Hindu calendars | |
| - Vikram Samvat | 334–335 |
| - Shaka Samvat | 200–201 |
| - Kali Yuga | 3379–3380 |
| Holocene calendar | 10278 |
| Iranian calendar | 344 BP – 343 BP |
| Islamic calendar | 355 BH – 354 BH |
| Japanese calendar | |
| Korean calendar | 2611 |
| Minguo calendar | 1634 before ROC 民前1634年 |
| Thai solar calendar | 821 |
Year 278 (CCLXXVIII) was a common 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 Probus and Lupus (or, less frequently, year 1031 Ab urbe condita). The denomination 278 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.