the correct (Stoic) path of virtue for a ruler. Tacitus and Dio suggest that Nero's early rule, during which he listened to Seneca and Burrus, was quite competent. However, the ancient sources suggest that, over time, Seneca and Burrus lost their influence over the emperor. In 59 they had reluctantly agreed to Agrippina's murder, and afterward Tacitus reports that Seneca had to write a letter justifying the murder to the Senate. In 58 AD the senator Publius Suillius Rufus made a series of public attacks on Seneca. These attacks, reported by Tacitus and Cassius Dio, included charges that, in a mere four years of service to Nero, Seneca had acquired a vast personal fortune of three hundred million sestertii by charging high interest on loans throughout Italy and the provinces. Suillius' attacks included claims of sexual corruption, with a suggestion that Seneca had slept with Agrippina. Tacitus, though, reports that Suillius was highly prejudiced: he had been a favorite of Claudius, and had been an embezzler and informant. In response, Seneca brought a series of prosecutions for corruption against Suillius: half of his estate was confiscated and he was sent into exile. However, the attacks reflect a criticism of Seneca that was made at the time and continued through later ages. Seneca was undoubtedly extremely rich: he had properties at Baiae and Nomentum, an Alban villa, and Egyptian estates. Cassius Dio even reports that the Boudica uprising in Britannia was caused by Seneca forcing large loans on the indigenous British aristocracy in the aftermath of Claudius's conquest of Britain, and then calling them in suddenly and aggressively. Seneca was sensitive to such accusations: his De Vita Beata ("On the Happy Life") dates from around this time and includes a defense of wealth along Stoic lines, arguing that properly gaining and spending wealth is appropriate behavior for a philosopher. Retirement After Burrus's death in 62, Seneca's influence declined rapidly; as Tacitus puts it (Ann. 14.52.1), mors Burri infregit Senecae potentiam ("the death of Burrus broke Seneca's power"). Tacitus reports that Seneca tried to retire twice, in 62 and 64 AD, but Nero refused him on both occasions. Nevertheless, Seneca was increasingly absent from the court. He adopted a quiet lifestyle on his country estates, concentrating on his studies and seldom visiting Rome. It was during these final few years that he composed two of his greatest works: Naturales quaestiones—an encyclopedia of