391

Millennium:	1st millennium
Centuries:	3rd century–4th century–5th century
Decades:	360s370s380s–390s–400s410s420s
Years:	388389390–391–392393394

391 in othercalendars

Gregorian calendar	391 CCCXCI
Ab urbe condita	1144
Assyrian calendar	5141
Balinese saka calendar	312–313
Bengali calendar	−202
Berber calendar	1341
Buddhist calendar	935
Burmese calendar	−247
Byzantine calendar	5899–5900
Chinese calendar	Canh dầnNiên(MetalTiger) 3087 or 3027 — to — Tân mão niên(MetalRabbit) 3088 or 3028
Coptic calendar	107–108
Discordian calendar	1557
Ethiopian calendar	383–384
Hebrew calendar	4151–4152
Hindu calendars
-Vikram Samvat	447–448
-Shaka Samvat	312–313
-Kali Yuga	3491–3492
Holocene calendar	10391
Iranian calendar	231 BP – 230 BP
Islamic calendar	238 BH – 237 BH
Javanese calendar	274–275
Julian calendar	391 CCCXCI
Korean calendar	2724
Minguo calendar	1521 beforeROC Dân tiền 1521 niên
Nanakshahi calendar	−1077
Seleucid era	702/703AG
Thai solar calendar	933–934
Tibetan calendar	Dương kim hổ niên (male Iron-Tiger) 517 or 136 or −636 — to — Âm kim thỏ niên (female Iron-Rabbit) 518 or 137 or −635

391(CCCXCI) was acommon year starting on Wednesdayof theJulian calendar,the 391st year of theCommon Era(CE) andAnno Domini(AD) designations, the 391st year of the1st millennium,the 91st year of the4th century,and the 2nd year of the390sdecade. As of the start of 391, the Gregorian calendar was 1 day ahead of the Julian calendar, which was the dominant calendar of the time.

Events

• Theodosius,theRoman Emperor,decrees thatChristianityshould be the onlyreligionallowed in theEmpire.