Nero was not expected to become Emperor because his maternal uncle , Caligula , had begun his reign at the age of 24 with enough time to produce his own heir . Nero 's mother , Agrippina , lost favour with Caligula and was exiled in 39 after her husband 's death . Caligula seized Nero 's inheritance and sent him to be brought up by his less wealthy aunt , Domitia Lepida , who was the mother of Valeria Messalina , Claudius 's third wife . Caligula , his wife Caesonia and their infant daughter Julia Drusilla were murdered on 24 January 41 . These events led Claudius , Caligula 's uncle , to become emperor . Claudius allowed Agrippina to return from exile .