| Millennium: | 1st millennium |
|---|---|
| Centuries: | 4th century – 5th century – 6th century |
| Decades: | 390s 400s 410s – 420s – 430s 440s 450s |
| Years: | 420 421 422 – 423 – 424 425 426 |
| 423 by topic | |
| Politics | |
| State leaders – Sovereign states | |
| Birth and death categories | |
| Births – Deaths | |
| Establishment and disestablishment categories | |
| Establishments – Disestablishments | |
| Gregorian calendar | 423 CDXXIII |
| Ab urbe condita | 1176 |
| Armenian calendar | N/A |
| Assyrian calendar | 5173 |
| Bahá'í calendar | -1421–-1420 |
| Bengali calendar | -170 |
| Berber calendar | 1373 |
| English Regnal year | N/A |
| Buddhist calendar | 967 |
| Burmese calendar | -215 |
| Byzantine calendar | 5931–5932 |
| Chinese calendar | 壬戌年十二月初四日 (3059/3119-12-4) — to —
癸亥年十一月十三日(3060/3120-11-13) |
| Coptic calendar | 139–140 |
| Ethiopian calendar | 415–416 |
| Hebrew calendar | 4183–4184 |
| Hindu calendars | |
| - Vikram Samvat | 479–480 |
| - Shaka Samvat | 345–346 |
| - Kali Yuga | 3524–3525 |
| Holocene calendar | 10423 |
| Iranian calendar | 199 BP – 198 BP |
| Islamic calendar | 205 BH – 204 BH |
| Japanese calendar | |
| Korean calendar | 2756 |
| Minguo calendar | 1489 before ROC 民前1489年 |
| Thai solar calendar | 966 |
Year 423 (CDXXIII) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Marinianus and Asclepiodotus (or, less frequently, year 1176 Ab urbe condita). The denomination 423 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.