(AD 14–68) Successors of Augustus , the first Roman emperor: Tiberius , Caligula , Claudius , and Nero .
It was a loosely defined set of kin relations rather than a direct bloodline. Tiberius's rule was competent, with notable accomplishments, but it ended in cruel tyranny. The insane Caligula was wild and capricious. Under Claudius, Rome experienced marked development. Under Nero the empire prospered, but he was given to excesses, and his reign ended amid rebellion and civil war.