31 BC

Millennium:	1st millennium BC
Centuries:	2nd century BC – 1st century BC – 1st century
Decades:	60s BC  50s BC  40s BC  – 30s BC –  20s BC  10s BC  0s BC
Years:	34 BC 33 BC 32 BC – 31 BC – 30 BC 29 BC 28 BC

31 BC in other calendars

Gregorian calendar	31 BC XXX BC
Ab urbe condita	723
Ancient Egypt era	XXXIII dynasty, 293
- Pharaoh	Cleopatra VII, 21
Ancient Greek era	187th Olympiad, year 2
Assyrian calendar	4720
Balinese saka calendar	N/A
Bengali calendar	−623
Berber calendar	920
Buddhist calendar	514
Burmese calendar	−668
Byzantine calendar	5478–5479
Chinese calendar	己丑年 (Earth Ox) 2666 or 2606     — to — 庚寅年 (Metal Tiger) 2667 or 2607
Coptic calendar	−314 – −313
Discordian calendar	1136
Ethiopian calendar	−38 – −37
Hebrew calendar	3730–3731
Hindu calendars
- Vikram Samvat	26–27
- Shaka Samvat	N/A
- Kali Yuga	3070–3071
Holocene calendar	9970
Iranian calendar	652 BP – 651 BP
Islamic calendar	672 BH – 671 BH
Javanese calendar	N/A
Julian calendar	31 BC XXX BC
Korean calendar	2303
Minguo calendar	1942 before ROC 民前1942年
Nanakshahi calendar	−1498
Seleucid era	281/282 AG
Thai solar calendar	512–513
Tibetan calendar	阴土牛年 (female Earth-Ox) 96 or −285 or −1057     — to — 阳金虎年 (male Iron-Tiger) 97 or −284 or −1056

Year 31 BC was either a common year starting on Tuesday, Wednesday or Thursday or a leap year starting on Tuesday or Wednesday of the Julian calendar. At the time, it was known as the Year of the Consulship of Antonius and Octavianus.

Events

• Gaius Julius Caesar Octavian becomes Roman Consul for the third time. His partner is Marcus Valerius Messalla Corvinus, replacing Mark Antony.
• Octavian establishes a bridgehead at the Gulf of Ambracia
• Marcus Vipsanius Agrippa sailed with 300 war galleys to the western Peloponnese. He occupied the Gulf of Corinth to cut off Antony's line of communication.
• Antony sets up camp at the promontory of Actium.
• Agrippa stormed Leucas. He took the garrison at Patrae.
• The Egyptian fleet retreats to Taenarus.
• Octavian takes court at Samos
• In the Judean Desert Herod the Great completes the fortress Masada.
• The Hellenistic period in art ends (or AD 14 by some scholars)