312

312 (CCCXII) was a leap year starting on Tuesday of the Julian calendar, the 312th year of the Common Era (CE) and Anno Domini (AD) designations, the 312th year of the 1st millennium, the 12th year of the 4th century, and the 3rd year of the 310s decade. As of the start of 312, the Gregorian calendar was 1 day ahead of the Julian calendar, which was the dominant calendar of the time.

Millennium:	1st millennium
Centuries:	3rd century – 4th century – 5th century
Decades:	280s  290s  300s  – 310s –  320s  330s  340s
Years:	309 310 311 – 312 – 313 314 315

312 in other calendars

Gregorian calendar	312 CCCXII
Ab urbe condita	1065
Assyrian calendar	5062
Balinese saka calendar	233–234
Bengali calendar	−281
Berber calendar	1262
Buddhist calendar	856
Burmese calendar	−326
Byzantine calendar	5820–5821
Chinese calendar	辛未年 (Metal Goat) 3008 or 2948     — to — 壬申年 (Water Monkey) 3009 or 2949
Coptic calendar	28–29
Discordian calendar	1478
Ethiopian calendar	304–305
Hebrew calendar	4072–4073
Hindu calendars
- Vikram Samvat	368–369
- Shaka Samvat	233–234
- Kali Yuga	3412–3413
Holocene calendar	10312
Iranian calendar	310 BP – 309 BP
Islamic calendar	320 BH – 319 BH
Javanese calendar	192–193
Julian calendar	312 CCCXII
Korean calendar	2645
Minguo calendar	1600 before ROC 民前1600年
Nanakshahi calendar	−1156
Seleucid era	623/624 AG
Thai solar calendar	854–855
Tibetan calendar	阴金羊年 (female Iron-Goat) 438 or 57 or −715     — to — 阳水猴年 (male Water-Monkey) 439 or 58 or −714

Events

• October 28 – Battle of Milvian Bridge: Constantine I defeats Maxentius and becomes the only Roman Emperor in the West.
• Construction of the Arch of Constantine in Rome begun.