Narcissus exercised great influence over Claudius and accumulated immense wealth. At first he allied himself with Claudius' third wife, Messalina Valeria, but fear that she and her lover, Gaius Silius, were conspiring to seize power made him join with others to have her executed (48). By failing to support Claudius' subsequent marriage to Agrippina the Younger, Narcissus lost influence in the government. The finance secretary, Pallas, who had favoured the match, became Claudius' favourite. Narcissus' power was further undermined when he backed Britannicus, son of Claudius and Messalina, for the succession even after Agrippina had persuaded Claudius to designate as his successor her own son (by a previous marriage), Lucius Domitius Ahenobarbus. In 54 Claudius died, perhaps poisoned by Agrippina. Domitius took power as the emperor Nero and immediately had Narcissus arrested. Shortly afterward the freedman committed suicide. (Encyclopedia Britannica)
Freedman who used his position as correspondence secretary (ab epistulis) to the Roman emperor Claudius (ruled 4154) to become, in effect, a minister of state.