AD 40

AD 40 (XL) was a leap year starting on Friday of the Julian calendar. At the time, it was known as the Year of the Consulship of Augustus without colleague (or, less frequently, year 793 Ab urbe condita). The denomination AD 40 for this year has been used since the Early Middle Ages, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Events

Emperor Caligula is consul without colleague.
Caligula starts on a campaign to conquer Britain, which fails miserably. He declares himself victorious regardless.
Noricum and Mauretania are incorporated into the Roman Empire.
Caligula reforms the principatus into a Hellenistic Autocracy. He distributes honors carelessly, declares himself a god and orders that all the heads of the Greek deity statues be replaced by his. He also appoints his horse, Incitatus, a senator.
Construction begins on the Pont du Gard aqueduct in Gallia Narbonensis (approximate date).{{cite journal|last1=Fabre|first1=Guilhem|last2=Fiches|first2=Jean-Luc|last3=Paillet|first3=Jean-Louis|year=1991|title=Interdisciplinary Research on the Aqueduct of Nimes and the Pont du Gard|journal=Journal of Roman Archaeology|volume=4|pages=63–88|doi=10.1017/S104775940001549X}}

The Vietnamese Trưng Sisters rebel against the rule of the Chinese Emperor Guang Wu of Han.

Christianity comes to Egypt as a church is founded in Alexandria. Mark the Evangelist founds the Church of Alexandria as the first Patriarch (traditional date).
An early Christian church is erected at Corinth (most probable date).
The traditional date of Saint James the Great meeting Our Lady of the Pillar in Spain

June 13 – Gnaeus Julius Agricola, Roman governor (d. AD 93)
Claudia Octavia, daughter of Claudius and Messalina (d. AD 62)
Dio Chrysostom, Greek philosopher and historian (d. c. 115)
Ma, Chinese empress of the Han dynasty (d. AD 79)
Pedanius Dioscorides, Greek physician and pharmacologist (d. AD 90)
Sextus Julius Frontinus, Roman general and military author (d. 103){{cite book |last1=Kvint |first1=Vladimir |title=Strategy for the Global Market: Theory and Practical Applications |date=2015 |publisher=Routledge |isbn=9781317485575 |page=8 |url=https://books.google.com/books?id=R_CoCgAAQBAJ&pg=PA8|language=en}}
Titus Petronius Secundus, Roman prefect (d. AD 97)

Gnaeus Domitius Ahenobarbus, husband of Agrippina the Younger (b. 17 BC)
Faustus Cornelius Sulla, Roman politician and suffect consul
Ptolemy of Mauretania, Roman client king (executed by Caligula)
Tiberius Julius Abdes Pantera, Roman soldier (hypothesized by numerous scholars to have been the father of Jesus)