666 (DCLXVI) was a common year starting on Thursday of the Julian calendar, the 666th year of the Common Era (CE) and Anno Domini (AD) designations, the 666th year of the 1st millennium, the 66th year of the 7th century, and the 7th year of the 660s decade. As of the start of 666, the Gregorian calendar was 3 days ahead of the Julian calendar, which was the dominant calendar of the time.

Millennium: 1st millennium
Centuries: 6th century7th century8th century
Decades: 630s  640s  650s  – 660s –  670s  680s  690s
Years: 663 664 665666667 668 669
666 in other calendars
Gregorian calendar666
DCLXVI
Ab urbe condita1419
Armenian calendar115
ԹՎ ՃԺԵ
Assyrian calendar5416
Balinese saka calendar587–588
Bengali calendar73
Berber calendar1616
Buddhist calendar1210
Burmese calendar28
Byzantine calendar6174–6175
Chinese calendar乙丑(Wood Ox)
3362 or 3302
    — to —
丙寅年 (Fire Tiger)
3363 or 3303
Coptic calendar382–383
Discordian calendar1832
Ethiopian calendar658–659
Hebrew calendar4426–4427
Hindu calendars
 - Vikram Samvat722–723
 - Shaka Samvat587–588
 - Kali Yuga3766–3767
Holocene calendar10666
Iranian calendar44–45
Islamic calendar45–46
Japanese calendarN/A
Javanese calendar557–558
Julian calendar666
DCLXVI
Korean calendar2999
Minguo calendar1246 before ROC
民前1246年
Nanakshahi calendar−802
Seleucid era977/978 AG
Thai solar calendar1208–1209
Tibetan calendar阴木牛年
(female Wood-Ox)
792 or 411 or −361
    — to —
阳火虎年
(male Fire-Tiger)
793 or 412 or −360

Events

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Births

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References

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