AD 23

AD 23 (XXIII) was a common year starting on Friday of the Julian calendar. At the time, it was known as the Year of the Consulship of Pollio and Vetus (or, less frequently, year 776 Ab urbe condita). The denomination AD 23 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

Greek geographer Strabo publishes Geographica, a work covering the world known to the Romans and Greeks at the time of Emperor Augustus – it is the only such book to survive from the ancient world.{{cite book|last=Roller|first=Duane W.|title=The building program of Herod the Great|year=1998|publisher=University of California Press|isbn=978-0-520-20934-3|page=65|url=https://books.google.com/books?id=2ZsB1yQOmyEC&dq=Strabo+publishes+Geography+23&pg=PA65}}
Emperor Tiberius' son Drusus Julius Caesar dies.{{cite book|last=Bunson|first=Matthew|title=Encyclopedia of the Roman empire|year=2002|publisher=Infobase Publishing|isbn=978-0-8160-4562-4|pages=187–188|url=https://books.google.com/books?id=T5tic2VunRoC&dq=Julius+Caesar+Drusus+died+23&pg=PA187|edition=2nd}} From that point forward, he seems to lose interest in the Empire and occupies himself with the pursuit of pleasure.
Lucius Aelius Sejanus begins to dominate the Roman Senate and Tiberius, after the death of Drusus.{{cite book|last1=Adkins|first1=Lesley|last2=Adkins|first2=Roy A.|title=Handbook to life in ancient Rome|year=2004|publisher=Infobase Publishing|isbn=978-0-8160-5026-0|page=23|url=https://books.google.com/books?id=zGY1Sqjwf8kC&dq=Lucius+Aelius+Sejanus+senate+23&pg=PA18|edition=2nd}}

Liu Xuan, a descendant of the Han dynasty royal family and leader of insurgents against the Xin dynasty, proclaims himself emperor against Wang Mang.{{cite book|last=Giele|first=Enno|title=Imperial decision-making and communication in early China: a study of Cai Yong's Duduan|year=2006|publisher=Otto Harrassowitz Verlag|isbn=978-3-447-05334-1|page=218|url=https://books.google.com/books?id=pb5veqFrpvIC&dq=Liu+Xuan+emperor+23&pg=PA218}}
July – After being under siege for two months, about 19,000 insurgents under Liu Xiu defeat 450,000 of Wang Mang's troops in the Battle of Kunyang, ushering in the fall of Wang Mang's Xin dynasty and restoration of the Han dynasty.{{cite book|last=Schram|first=Stuart R.|title=Mao's road to power: revolutionary writings 1912–1949|year=1992|publisher=M.E. Sharpe|isbn=978-1-56324-457-5|page=366|url=https://books.google.com/books?id=K8K7b_nC6BsC&dq=Battle+of+Kunyang+23&pg=PA366|volume=1}}
October 6 – Emperor Liu Xuan's forces kill Wang Mang at the end of a three-day siege.

Pliny the Elder, Roman scientist and writer{{cite book|last=Healy|first=John F.|title=Pliny the Elder on science and technology|year=1999|publisher=Oxford University Press|isbn=978-0-19-814687-2|page=1|url=https://books.google.com/books?id=Hz6D4H-s5psC&dq=Pliny+the+Elder+born+23&pg=PA1}} (d. 79 AD)

September 14 – Drusus Julius Caesar, son of Emperor Tiberius{{cite book|last1=Bowman|first1=Alan K.|last2=Champlin|first2=Edward|last3=Lintott|first3=Andrew|title=The Augustan Empire, 43 B.C.–A.D. 69|year=1996|publisher=Cambridge University Press|isbn=978-0-521-26430-3|pages=213|url=https://books.google.com/books?id=JZLW4-wba7UC&dq=Drusus+poisoned+September+14%2C+23&pg=PA213|edition=2nd}} (b. 14 BC)
October 6 – Wang Mang, Chinese emperor of the Xin dynasty (b. c. 45 BC){{cite book|last=Clark|first=Anthony E.|title=Ban Gu's history of early China|year=2008|publisher=Cambria Press|isbn=978-1-60497-561-1|page=110|url=https://books.google.com/books?id=cUF0ZCTRPwEC&dq=Wang+Mang+October+6%2C+23&pg=PA110}}
Juba II, king of Mauretania{{cite book|last=Rocca|first=Samuel|title=Herod's Judaea: a Mediterranean state in the classical world|year=2008|publisher=Mohr Siebeck|isbn=978-3-16-149717-9|page=58|url=https://books.google.com/books?id=WaUSt9sQP2wC&dq=Juba+II+died+23&pg=PA58}} (b. c. 50 BC)
Liu Xin, Chinese astronomer, mathematician and politician{{cite book|last=Yunis|first=Harvey|title=Written texts and the rise of literate culture in ancient Greece|year=2003|publisher=Cambridge University Press|isbn=978-0-521-80930-6|page=125|url=https://books.google.com/books?id=hMve3wMT4g0C&dq=Liu+Xin+died+23&pg=PA124}} (b. c. 50 BC)
Liu Yan, Chinese general and politician
Servius Cornelius Lentulus Maluginensis, Roman statesman
Wang, Chinese empress of the Xin dynasty (b. 8 BC)