Properly Gaius Julius Caesar Augustus Germanicus (31 August AD 12 – 24 January AD 41) was Roman emperor from AD 37–41.
Born Gaius Julius Caesar Germanicus (not to be confused with Julius Caesar), Caligula was a member of the house of rulers conventionally known as the Julio-Claudian dynasty.
He was the great-nephew and nominated heir of Emperor Tiberius, and Tiberius's adopted grandson by virtue of his adoption of Caligula's biological father Germanicus.
The young Gaius earned the nickname "Caligula" (meaning "little soldier's boot", the diminutive form of caliga, hob-nailed military boot) from his father's soldiers while accompanying him during his campaigns in Germania.
When Germanicus died at Antioch in AD 19, his wife Agrippina the Elder returned with her six children to Rome, where she became entangled in a bitter feud with Tiberius.
The conflict eventually led to the destruction of her family, with Caligula as the sole male survivor.
Untouched by the deadly intrigues, Caligula accepted the invitation to join the Emperor in AD 31 on the island of Capri, where Tiberius had withdrawn five years earlier.
With the death of Tiberius in AD 37, Caligula succeeded his grand uncle and adoptive grandfather as emperor.
There are few surviving sources about the reign of Emperor Caligula, although he is described as a noble and moderate ruler during the first six months of his reign.
After this, the sources focus upon his cruelty, sadism, extravagance, and sexual perversion, presenting him as an insane tyrant.
While the reliability of these sources is questionable, it is known that during his brief reign, Caligula worked to increase the unconstrained personal power of the emperor, as opposed to countervailing powers within the principate.
He directed much of his attention to ambitious construction projects and luxurious dwellings for himself, and initiated the construction of two aqueducts in Rome: the Aqua Claudia and the Anio Novus.