23 BC

23 BC in various calendars
Gregorian calendar	23 BC; XXIII BC
Ab urbe condita	731
Ancient Greek Olympiad (summer)	189th Olympiad, year 2
Assyrian calendar	4728
Balinese saka calendar	N/A
Bengali calendar	−616 – −615
Berber calendar	928
Buddhist calendar	522
Burmese calendar	−660
Byzantine calendar	5486–5487
Chinese calendar	丁酉年 (Fire Rooster); 2675 or 2468; — to —; 戊戌年 (Earth Dog); 2676 or 2469
Coptic calendar	−306 – −305
Discordian calendar	1144
Ethiopian calendar	−30 – −29
Hebrew calendar	3738–3739
Hindu calendars
- Vikram Samvat	34–35
- Shaka Samvat	N/A
- Kali Yuga	3078–3079
Holocene calendar	9978
Iranian calendar	644 BP – 643 BP
Islamic calendar	664 BH – 663 BH
Javanese calendar	N/A
Julian calendar	23 BC; XXIII BC
Korean calendar	2311
Minguo calendar	1934 before ROC; 民前1934年
Nanakshahi calendar	−1490
Seleucid era	289/290 AG
Thai solar calendar	520–521
Tibetan calendar	མེ་མོ་བྱ་ལོ་; (female Fire-Bird); 104 or −277 or −1049; — to —; ས་ཕོ་ཁྱི་ལོ་; (male Earth-Dog); 105 or −276 or −1048

Year 23 BC was either a common year starting on Saturday or Sunday or a leap year starting on Friday, Saturday or Sunday of the Julian calendar (the sources differ, see leap year error for further information) and a common year starting on Friday of the Proleptic Julian calendar. At the time, it was known as the Year of the Consulship of Augustus and Varro (or, less frequently, year 731 Ab urbe condita). The denomination 23 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.

Events

Caesar Augustus becomes Roman consul for the eleventh time. His co-consul is Aulus Terentius Varro Murena.
Augustus relinquishes the position of consul, retains that of tribune of Rome, and assumes that of Princeps, or "First Citizen." (see Roman Empire).
Augustus gets seriously ill: he gives Agrippa his signet ring and grants him the title imperium pro consule.
Marcus Claudius Marcellus (nephew of Augustus) falls ill from a fever shortly after his uncle recovers and dies at the age of nineteen while serving as an aedile.
The Nubians, led by queen Kandake Amanirenas, take the initiative against the Roman Empire, and attack the Roman province of Egypt moving towards Elephantine.
In response to Meroë's incursions into Upper Egypt, the Roman legions move south and raze Napata. (History of Sudan).
Herod the Great builds a palace in Jerusalem and the fortress Herodium in Judaea. He also marries his third wife, named Mariamne, the daughter of high priest Simon.
Following coinage reform, the as is struck in reddish pure copper, instead of bronze. The denominations of sestertius and dupondius are introduced as large bronze coins.

The Roman writer, architect and engineer Marcus Vitruvius Pollio finishes writing De Architectura (known today as The Ten Books of Architecture), a treatise in Latin on architecture, and perhaps the first work about this discipline.