 | This article relies largely or entirely on a single source. (March 2019) |
| Millennium: | 1st millennium |
|---|---|
| Centuries: | |
| Decades: | |
| Years: |
| 421 by topic |
|---|
| Leaders |
| Categories |
| Gregorian calendar | 421 CDXXI |
| Ab urbe condita | 1174 |
| Assyrian calendar | 5171 |
| Balinese saka calendar | 342–343 |
| Bengali calendar | −172 |
| Berber calendar | 1371 |
| Buddhist calendar | 965 |
| Burmese calendar | −217 |
| Byzantine calendar | 5929–5930 |
| Chinese calendar | 庚申年 (Metal Monkey) 3118 or 2911 — to — 辛酉年 (Metal Rooster) 3119 or 2912 |
| Coptic calendar | 137–138 |
| Discordian calendar | 1587 |
| Ethiopian calendar | 413–414 |
| Hebrew calendar | 4181–4182 |
| Hindu calendars | |
| - Vikram Samvat | 477–478 |
| - Shaka Samvat | 342–343 |
| - Kali Yuga | 3521–3522 |
| Holocene calendar | 10421 |
| Iranian calendar | 201 BP – 200 BP |
| Islamic calendar | 207 BH – 206 BH |
| Javanese calendar | 305–306 |
| Julian calendar | 421 CDXXI |
| Korean calendar | 2754 |
| Minguo calendar | 1491 before ROC 民前1491年 |
| Nanakshahi calendar | −1047 |
| Seleucid era | 732/733 AG |
| Thai solar calendar | 963–964 |
| Tibetan calendar | 阳金猴年 (male Iron-Monkey) 547 or 166 or −606 — to — 阴金鸡年 (female Iron-Rooster) 548 or 167 or −605 |
Year 421 (CDXXI) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Agricola and Eustathius (or, less frequently, year 1174 Ab urbe condita). The denomination 421 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.