Caligula (Latin: Gaius Julius Caesar Augustus Germanicus; August 31 CE 12 – January 24, CE 41), also known as Gaius, is Roman Emperor from 37 CE to 41 CE.

Caligula is a member of the house of rulers conventionally known as the Julio-Claudian dynasty.

Caligula's father Germanicus, the nephew and adopted son of Emperor Tiberius, is a very successful general and one of Rome's most beloved public figures.

The young Gaius earns the nickname Caligula (meaning "little soldier's boot", the diminutive form of caliga, a hob-nailed military boot) from his father's soldiers while accompanying him during his campaigns in Germania.

When Germanicus dies at Antioch in 19 CE, his wife Agrippina the Elder returnsto Rome with her six children where she becomes entangled in an increasingly bitter feud with Tiberius.

This conflict eventually leads to the destruction of her family, with Caligula as the sole male survivor.

Unscathed by the deadly intrigues, Caligula accepts the invitation to join the emperor on the island of Capri in 31, where Tiberius himself had withdrawn five years earlier.

At the death of Tiberius in 37, Caligula succeeds his great-uncle and adoptive grandfather.

There are few surviving sources on Caligula's reign, although he is described as a noble and moderate ruler during the first two years of his rule.

After this, the sources focus upon his cruelty, extravagance, and sexual perversity, presenting him as an insane tyrant.

While the reliability of these sources has increasingly been called into question, 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 notoriously luxurious dwellings for himself.

However, he initiated the construction of two new aqueducts in Rome: the Aqua Claudia and the Anio Novus.

During his reign, the Empire annexed the Kingdom of Mauretania and made it into a province.

In early 41 CE, Caligula is assassinated as the result of a conspiracy involving officers of the Praetorian Guard, as well as members of the Roman Senate and of the imperial court.

The conspirators' attempt to use the opportunity to restore the Roman Republic is thwarted: on the same day the Praetorian Guard declares Caligula's uncle Claudius emperor in his place.