Was Seneca a hypocrite for preaching Stoic detachment while enormously rich?

Many have said so, starting in his own lifetime, but the case is less clear-cut than it looks. Seneca was a Stoic philosopher of ancient Rome, but also a statesman, a dramatist and a satirist. When Nero became emperor in 54, Seneca became his advisor and, with the praetorian prefect Burrus, provided competent government for the first five years of the reign. In his own time he was accused of hypocrisy, or at least of a less than "Stoic" lifestyle.

The sharpest attack came in AD 58, when the senator Suillius charged that in four years of service to Nero, Seneca had amassed three hundred million sestertii by charging high interest on loans across Italy and the provinces. Tacitus reports that Suillius was highly prejudiced: a favorite of Claudius, and an embezzler and informant. Seneca answered with prosecutions for corruption, and Suillius lost half his estate and was sent into exile. Still, Seneca was undoubtedly extremely rich, with properties at Baiae and Nomentum, an Alban villa and Egyptian estates.

Seneca was sensitive to such accusations, and his answer was a philosophical one. His essay On the Happy Life, from around this time, argues that properly gaining and spending wealth is appropriate behavior for a philosopher. That fits the Stoic category of "preferred indifferents": health and wealth have value, but only virtue is good. Seneca returns again and again to how they do not contribute to our happiness, yet he does not suggest they should be regarded dismissively.

So being rich was not in itself un-Stoic; the open question is whether his conduct matched his words. A translator of his letters calls that contrast between teaching and practice the stock criticism of Seneca down the centuries. Defenders reply that the negative image rests almost entirely on the prejudiced Suillius, and that his writings are not autobiography: Seneca creates a literary persona for himself.