There are few surviving sources on Caligula's reign, although he is described as a noble and moderate ruler during the first six months 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.