There are few surviving sources about the reign of Caligula, though he is described as a noble and moderate emperor during the first six months of his rule. 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. During his reign, the empire annexed the client kingdom of Mauretania as a province.