Year 1 BC was a common year starting on Friday or Saturday (link will display the full calendar) of the Julian calendar (the sources differ, see leap year error for further information) and a leap year starting on Thursday of the Proleptic Julian calendar. It is also a leap year starting on Saturday, in the Proleptic Gregorian calendar. At the time, it was known as the Year of the Consulship of Lentulus and Piso (or, less frequently, year 753 Ab urbe condita). The denomination 1 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. The following year is 1 AD in the widely used Julian calendar, which does not have a "year zero".
|Millennium:||1st millennium BC|
|Gregorian calendar||1 BC|
|Ab urbe condita||753|
|Ancient Greek era||194th Olympiad, year 4|
|Balinese saka calendar||N/A|
|Chinese calendar||己未年 (Earth Goat)|
2696 or 2636
— to —
庚申年 (Metal Monkey)
2697 or 2637
|Coptic calendar||−284 – −283|
|Ethiopian calendar||−8 – −7|
|- Vikram Samvat||56–57|
|- Shaka Samvat||N/A|
|- Kali Yuga||3100–3101|
|Iranian calendar||622 BP – 621 BP|
|Islamic calendar||641 BH – 640 BH|
|Julian calendar||1 BC|
|Minguo calendar||1912 before ROC|
|Seleucid era||311/312 AG|
|Thai solar calendar||542–543|
126 or −255 or −1027
— to —
127 or −254 or −1026
- Emperor Ai of Han dies and is succeeded by his 8-year-old cousin Ping of Han. Wang Mang is appointed regent by Grand Empress Dowager Wang Zhengjun, who is also his aunt.
- Former regent Dong Xian, who was previously Emperor Ai of Han's lover, commits suicide with his wife.
- Gaius Caesar marries Livilla, daughter of Antonia Minor and Nero Claudius Drusus, in an effort to gain prestige.
- Estimated birth of Jesus, in the Christian religion, as assigned by Dionysius Exiguus in his Anno Domini era; according to most scholars, Dionysius used the word "incarnation", but it is not known whether he meant conception or birth. However, at least one scholar thinks Dionysius placed the incarnation of Jesus in the next year, AD 1. Most modern scholars do not consider Dionysius' calculations authoritative, themselves placing the event several years earlier (see Chronology of Jesus).
- August 15 – Ai of Han, Chinese emperor of the Han Dynasty (b. 27 BC)
- Dong Xian, Chinese politician and commander-in-chief (b. 23 BC)
- Xiaoai, Chinese empress and wife of Ai of Han
- Zhao Feiyan, Chinese empress and wife of Cheng of Han (b. 45 BC)
- Year zero for the different conventions that historians and astronomers use for "BC" years
- Georges Declercq, Anno Domini: The origins of the Christian Era (Turnhout, Belgium: Brepols, 2000), pp.143–147.
- G. Declercq, "Dionysius Exiguus and the introduction of the Christian Era", Sacris Erudiri 41 (2002) 165–246, pp.242–246. Annotated version of a portion of Anno Domini.
- James D. G. Dunn, Jesus Remembered, Eerdmans Publishing (2003), page 324.
- Fairbank, John (1986). The Cambridge History of China: Volume 1, The Ch'in and Han Empires, 221 BC-AD 220. Cambridge University Press. p. 227. ISBN 9780521243278.
- Loewe, Michael (2018) . Crisis and Conflict in Han China. Routledge. ISBN 9780429849107.