QuoteThe "abolished by law" is what I have heard but have not researched. I thought I had read that Augustus closed all the schools, not just the Epicurean, and that would predate the Christian issue. Presumably this would have hurt all the schools, but if the Epicureans were "taking Italy by storm" as Cicero complained, then this would have been especially damaging to the Epicureans.
The closing of the schools of philosophy did not happen until much, much later, under Justinian in 529. But Constantine converted the Empire in the 4th century, and then Julian the Apostate deconverted--but his paganism was not less authoritarian for that, as you may read in his own words here.
In attempting to resurrect the piety of old Rome, he singled out the Epicureans and the Pyrrhonists as being against his project. Himerius was a secretary of Justinian's, and the Encyclopedia Brittanica of 1911 says:
QuoteOther declamations, only known from the excerpts in Photius, were imaginary orations put into the mouth of famous persons—Demosthenes advocating the recall of Aeschines from banishment, Hypereides supporting the policy of Demosthenes, Themistocles inveighing against the king of Persia, an orator unnamed attacking Epicurus for atheism before Julian at Constantinople.