Julian's initial toleration of Christianity is coupled with a determination to revive paganism and raise it to the level of an official religion with an established hierarchy.

The new emperor, who apparently sees himself as the head of a pagan church, performs animal sacrifices and is a staunch defender of a sort of pagan orthodoxy, issuing doctrinal instructions to his clergy.

Not surprisingly, this incipient fanaticism soon leads from apparent toleration to outright suppression and persecution of Christians.

Pagans are openly preferred for high official appointments, and Christians are expelled from the army and prohibited from teaching classical literature and philosophy.

The latter action leads his contemporary and comrade-in-arms Ammianus Marcellinus, who admires Julian's virtues and is himself an adherent of the traditional religion, to censure the emperor: That was inhumane, and better committed to oblivion, that he forbade teachers of rhetoric and literature to practice their profession if they were followers of the Christian religion.

Julian writes an attack on Christianity, Against the Galileans (known today only by fragmentary citation).

“The trickery of the Galileans”—his usual term—has nothing divine in it, he argues; it appeals to rustics only, and it is made up of fables and irrational falsehoods.

Though a professed Neoplatonist and a sun worshiper, Julian himself is, according to Ammianus, an addict of superstition rather than religion.

Julian penalizes Christian cities, and burns churches in Damascus and …

…Beirut.

Bishops, including the great Athanasius of Alexandria, are banished; one is tortured horribly.

Bacchus, the Greco-Roman god associated with nature, wine, and ecstasy, is installed in the Christian basilicas of Emesa (modern Hims, Syria) and …

…Epiphaneia (modern Hamah, Syria).

Julian holds a tribunal at the city of Chalcedon, which is at this time a suburb of Constantinople, shortly after the death of Constantius.

Saturninius Secundus Salutius, who is raised to the rank of Praetorian Prefect, is given the chief oversight and with him are associated Claudius Mamertinus (another civilian), and four military commanders, Arbitio, Agilo, Nevitta and Jovinus.

The first two are ex-officers of Constantius, while the other two had served with Julian.

At this tribunal a large part of Constantius's ministers are brought to trial.

In charge of the daily inquisitions is Arbitio, "while the others were present merely for show" according to historian Ammianus Marcellinus.

Palladius, Taurus, Euagrius, Saturninus and Cyrinus are known to have been exiled.

Florentius, Ursulus and Eusebius are condemned to death.

Apodemius and Paulus Catena are even burned alive.

Another Florentius is imprisoned on a Dalmatian island.

As Constantius II died on October 5, 361, all this must have happened in late 361 and early 362.

Julian prefers Judaism to Christianity, considering Judaism closer to his conception of the Greco-Roman viewpoint.

He announces his intention of rebuilding the Jewish Temple in Jerusalem as part of his apostasy and as an attempt to sway the Himyarite kingdom in Arabia away from Persia.

His project to rebuild the Temple is designed rather to insult the Christians than to please the Jews, who, for long accustomed to the worship of the synagogue, would find the revival of animal sacrifice acutely embarrassing.

The plan is dropped when it is reported (as it had been on an earlier occasion, and will be on a later one) that “balls of fire” had issued from the old foundations and scared away the workers.

Constantius had sent Paulus “Catena” from Britain to Egypt with the excuse that the consultations to and responses from the oracle of Besa had displeased him.

Paulus had set up a kangaroo court and, with near full imperial power delegated to him, began summarily passing judgment on suspected traitors.

His convictions were numerous and his punishments and methods of torture cruel.

He had summoned cartloads of shackled prisoners from all over the eastern empire.

Some had their property confiscated and were exiled, while others were placed on racks and turned on wheels before being mutilated and executed.

Paulus under Constantius’s successor, Julian, is in around 362 burned alive for his crimes.

The invasion of Persian territory, always a lure in antiquity, is one to which Julian is not immune.

Motivated by a desire for military glory and a decision to reassert Rome's preeminence in the East, he assembles, despite counsels of prudence from Rome and the Levant, the largest Roman army (sixty-five thousand strong and backed by a river fleet) ever to head a campaign against Persia.

Despite counsels of prudence from Rome and the Levant, Julian leads his huge force into Sassanian territory in 363, wreaking havoc and approaching the very gates of Ctesiphon on the Tigris (below modern Baghdad), a major Sassanian city.

The Persians, aided by the desert, famine, treachery, and the incompetence of the Roman army—corrupted perhaps by large numbers of hostile Christians—once again prove themselves superior.

On June 25, during a disastrous retreat from the walls of Ctesiphon, below modern Baghdad, Julian is wounded by a spear, thrown “no one knew whence,” which pierces his liver.

He dies the next night at age thirty-one, having been emperor for twenty months.

Julian's successor, Jovian, chosen by the army's general staff, is a Christian, but not a fanatic.

To extricate his army from Persia, the new ruler immediately concludes an ignominious peace with Shapur, ceding to the Persians a good part of Galerian's conquests of 298, including all Roman territory east of the Tigris River, …

…together with the cities of Singara (modern Sinjar, Iraq) and …