Caligula was the Roman emperor from AD 37–41. Historical sources focus upon his cruelty, sadism, extravagance, and sexual perversity, presenting him as an insane tyrant. While the reliability of these sources is questionable, it is known that during his brief, four year 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.