421 BC

Millennium: 1st millennium BC
Centuries:
Decades:
Years:
421 BC in various calendars
Gregorian calendar421 BC
CDXXI BC
Ab urbe condita333
Ancient Egypt eraXXVII dynasty, 105
- PharaohDarius II of Persia, 3
Ancient Greek era89th Olympiad, year 4
Assyrian calendar4330
Balinese saka calendarN/A
Bengali calendar−1013
Berber calendar530
Buddhist calendar124
Burmese calendar−1058
Byzantine calendar5088–5089
Chinese calendar己未年 (Earth Goat)
2277 or 2070
    — to —
庚申年 (Metal Monkey)
2278 or 2071
Coptic calendar−704 – −703
Discordian calendar746
Ethiopian calendar−428 – −427
Hebrew calendar3340–3341
Hindu calendars
 - Vikram Samvat−364 – −363
 - Shaka SamvatN/A
 - Kali Yuga2680–2681
Holocene calendar9580
Iranian calendar1042 BP – 1041 BP
Islamic calendar1074 BH – 1073 BH
Javanese calendarN/A
Julian calendarN/A
Korean calendar1913
Minguo calendar2332 before ROC
民前2332年
Nanakshahi calendar−1888
Thai solar calendar122–123
Tibetan calendar阴土羊年
(female Earth-Goat)
−294 or −675 or −1447
    — to —
阳金猴年
(male Iron-Monkey)
−293 or −674 or −1446

Year 421 BC was a year of the pre-Julian Roman calendar. At the time, it was known in Rome as the Year of the Consulship of Vibulanus and Barbatus (or, less frequently, year 333 Ab urbe condita). The denomination 421 BC 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.